commit babcbd8be1d4b12fa3bcc52a3153ee64d92e2dbf
parent 23964fcb20363cce1e763322c3cedb84864f22e9
Author: Amit Dutta <amitdutta4255@gmail.com>
Date: Fri, 20 Mar 2026 14:16:06 +0530
[2026-03-20] : .\Semester_1\R : R practice
Diffstat:
8 files changed, 791 insertions(+), 6 deletions(-)
diff --git a/Semester_1/R/Code/R_Code-10.r b/Semester_1/R/Code/R_Code-10.r
@@ -0,0 +1,11 @@
+# Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Create a numeric vector of student exam scores.
+# Write a single line of code that evaluates these scores and
+# outputs "Pass" for any score 50 or above, and "Fail" for any score below 50.
+
+score <- c(45, 26, 89, 21, 75, 99, 13, 68, 85)
+
+ifelse(score < 50, "Fail", "Pass")+
\ No newline at end of file
diff --git a/Semester_1/R/Code/R_Code-11.r b/Semester_1/R/Code/R_Code-11.r
@@ -0,0 +1,20 @@
+# Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Write a while loop that starts with a multiplier of 1.
+# The loop should multiply the current multiplier by 4,
+# assign it to a result variable, and print the result.
+# The loop should exit if the result exceeds 100; otherwise,
+# increment the multiplier by 1.
+
+num = 1
+while(TRUE) {
+ result <- num * 4
+ print(result)
+
+ if (result > 100) {
+ break
+ }
+ num = num + 1
+}
diff --git a/Semester_1/R/Code/R_Code-12.r b/Semester_1/R/Code/R_Code-12.r
@@ -0,0 +1,14 @@
+# Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Write a custom function named calculate_area that takes
+# two parameters: length and width. The width parameter should have
+# a default value of 5. The function should print the product of the
+# two parameters. Finally, call your function passing only the value 12 for the length.
+
+calculate_area <- function(length, width = 5) {
+ print(length * width)
+}
+
+calculate_area(12)+
\ No newline at end of file
diff --git a/Semester_1/R/Code/R_Code-13.r b/Semester_1/R/Code/R_Code-13.r
@@ -0,0 +1,13 @@
+# Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Create a list named student_record containing a string,
+# an integer, and a numeric vector of two grades. Then, add the
+# logical value TRUE to the end of the list, ensuring the original
+# student_record variable is updated. Print the final list.
+
+student_record <- list("Amit Dutta", 95, c(95, 96))
+print(student_record)
+student_record <- append(student_record, TRUE)
+print(student_record)+
\ No newline at end of file
diff --git a/Semester_1/R/Code/R_Code-14.r b/Semester_1/R/Code/R_Code-14.r
@@ -0,0 +1,17 @@
+# Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Write an if...else if...else block that evaluates a newly created temperature variable.
+# * If the temperature is strictly greater than 30, print: "30+ is too hot!"
+# * If the temperature is between 20 and 30 (inclusive), print: "Perfect weather."
+# * Otherwise, print: "It is quite cold."
+
+temperature <- 29
+if(temperature > 30) {
+ print("30+ is too hot!")
+} else if(temperature >= 20 && temperature <= 30) {
+ print("Perfect weather")
+} else {
+ print("It is quite cold.")
+}+
\ No newline at end of file
diff --git a/Semester_1/R/Code/R_Code-9.r b/Semester_1/R/Code/R_Code-9.r
@@ -6,9 +6,10 @@
# a and b. Give a a default value of 2. The function should print the result
# of a raised to the power of b (a^b).
-power <- function (a, b) {
+power <- function (a = 2, b) {
return (a^b)
}
a <- 2
b <- 3
-print(power(a, b))-
\ No newline at end of file
+print(power(a, b))
+print(power("b" = b))+
\ No newline at end of file
diff --git a/Semester_1/R/README.md b/Semester_1/R/README.md
@@ -0,0 +1,551 @@
+# R Programming: Last-Minute Exam Cheat Sheet
+
+This document is designed for rapid review before your exam. It covers essential core concepts, crucial R functions (and their quirks), and all 20 reserved words.
+
+## Crucial Rules to Remember
+
+1. **Variable Naming:** Variables can start with letters or a period (`.`). However, if they start with a period, they **cannot** be followed by a digit (`.2var` is illegal).
+2. **1-Based Indexing:** Unlike C, Python, or Java (where arrays start at 0), **R indices start at 1**. The first element of `vector_x` is `vector_x[1]`.
+3. **Negative Indexing:** Using a minus sign *excludes* that element. `my_list[-2]` returns the list WITHOUT the 2nd element.
+4. **Type Coercion:** If you mix data types in a vector (e.g., `c(1, "A", TRUE)`), R will aggressively force them into a single type. The hierarchy is: `logical` -> `integer` -> `numeric` -> `character`.
+5. **Returning Multiple Values:** A function can only return ONE object. To return multiple answers, bundle them into a list: `return(list("Area"=area, "Perimeter"=peri))`.
+6. **Assignment:** While `=` works, `<-` is the strictly preferred assignment operator in R. `=` is mainly used for assigning arguments inside function calls.
+7. **Null vs NA vs NaN:**
+ - `NA`: Missing data (Not Available).
+ - `NaN`: Mathematical impossibility (Not a Number, like `0/0`).
+ - `NULL`: An empty object / undefined.
+
+## Essential Operators
+
+| Operator | Name | Category | Description |
+| :--- | :--- | :--- | :--- |
+| `<-` | Left Assignment | Assignment | Assigns a value to a variable (Leftward). |
+| `->` | Right Assignment | Assignment | Assigns a value to a variable (Rightward). |
+| `%%` | Modulo | Arithmetic | Modulo (finds the remainder of division, e.g., `5 %% 2 == 1`). |
+| `^` | Exponent | Arithmetic | Exponent/Power (e.g., `2^3 == 8`). |
+| `<` / `>` | Less/Greater Than | Relational | Strictly less than / strictly greater than. |
+| `<=` / `>=` | Less/Greater or Equal | Relational | Less than or equal to / Greater than or equal to. |
+| `==` / `!=` | Equality / Inequality | Relational | Equals to / Not equals to. |
+| `&` | Element-wise AND | Logical | Element-wise AND (returns TRUE only if both are TRUE). |
+| `&&` | Logical AND | Logical | Evaluates ONLY the first element of a vector. Used mainly in if-statements. |
+| `|` | Element-wise OR | Logical | Element-wise OR (returns TRUE if at least one is TRUE). |
+| `||` | Logical OR | Logical | Evaluates ONLY the first element of a vector. Used mainly in if-statements. |
+| `!` | Logical NOT | Logical | NOT operator (reverses a boolean, `!TRUE == FALSE`). |
+
+---
+
+## Built-In Constants
+
+| Constant | Value | Description |
+| :--- | :--- | :--- |
+| `pi` | `3.141593...` | The mathematical constant pi. |
+| `LETTERS` | `"A", "B", "C" ... "Z"` | A character vector of the 26 uppercase English letters. |
+| `letters` | `"a", "b", "c" ... "z"` | A character vector of the 26 lowercase English letters. |
+| `month.abb` | `"Jan", "Feb" ... "Dec"` | A character vector of the 3-letter abbreviations for the English months. |
+| `month.name` | `"January", "February"...` | A character vector of the full names of the English months. |
+
+---
+
+## All 20 R Reserved Words (Keywords)
+
+Reserved words have special meaning in R and **cannot** be used as variable or function names.
+
+| Reserved Word | Usage / Description | Quick Example |
+| :--- | :--- | :--- |
+| `if` | Starts a conditional control-flow statement. | `if (x > 0) print("Pos")` |
+| `else` | Fallback for an `if` statement when the condition is FALSE. | `else print("Neg")` |
+| `while` | Loop that executes as long as a condition is TRUE. | `while (x < 5) x <- x + 1` |
+| `repeat` | Infinite loop that requires a `break` statement to exit. | `repeat { if(x>5) break }` |
+| `for` | Loop that iterates over a list, vector, or sequence. | `for (i in 1:5) print(i)` |
+| `function` | Keyword used to declare a user-defined function. | `f <- function(x) { x + 1 }` |
+| `in` | Used within `for` loops to specify the sequence to iterate over. | `for (item in my_list)` |
+| `next` | Skips the current loop iteration and moves to the next one. | `if (i %% 2 == 0) next` |
+| `break` | Immediately terminates the execution of a loop. | `if (i == 5) break` |
+| `TRUE` | Logical constant representing True (boolean 1). | `is_valid <- TRUE` |
+| `FALSE` | Logical constant representing False (boolean 0). | `is_valid <- FALSE` |
+| `NULL` | Represents the null object / undefined data. | `my_var <- NULL` |
+| `Inf` | Constant representing positive infinity. | `1 / 0` -> `Inf` |
+| `NaN` | Not a Number (e.g., 0/0). | `0 / 0` -> `NaN` |
+| `NA` | Logical missing value (Not Available). | `c(1, NA, 3)` |
+| `NA_integer_` | Missing value specifically typed as an integer. | `c(1L, NA_integer_)` |
+| `NA_real_` | Missing value specifically typed as a double/numeric. | `c(1.5, NA_real_)` |
+| `NA_complex_` | Missing value specifically typed as a complex number. | `c(1+2i, NA_complex_)` |
+| `NA_character_` | Missing value specifically typed as a character/string. | `c("A", NA_character_)` |
+| `...` | Ellipsis operator used to pass a variable number of arguments into a function. | `f <- function(...) print(list(...))` |
+
+---
+
+## Essential Functions Reference
+
+| Function | Usage | Example Result-Output | Edge Case / Quirks |
+| :--- | :--- | :--- | :--- |
+| `print()` | Prints values and variables to the console. | `print("R")` -> `[1] "R"` | Printing `NULL` prints `NULL` (without the `[1]` index). |
+| `cat()` | Prints variables and strings concatenated, used with basic types. | `cat("Hi\n")` -> `Hi` | `cat(NULL)` outputs absolutely nothing, no errors. |
+| `help()` | Views help documentation for functions or keywords. | `help(sum)` -> *(Opens help viewer)* | Searching for special operators requires backticks: `help("+")`. |
+| `class()` | Returns the data type or class of a variable. | `class(TRUE)` -> `[1] "logical"` | If applied to a mixed vector `c(1, "a")`, returns `"character"` (coercion). |
+| `paste()` | Prints a string and variable together with a default space separator. | `paste("Hi", "R")` -> `[1] "Hi R"` | `paste("A", NA)` outputs `"A NA"` (NA is converted to a string). |
+| `paste0()` | Prints a string and variable together with NO default space separator. | `paste0("Hi", "R")` -> `[1] "HiR"` | Recycles shorter vectors: `paste0("A", 1:3)` -> `"A1" "A2" "A3"`. |
+| `sprintf()` | Prints formatted strings using format specifiers like %s, %d, %f. | `sprintf("%d", 123)` -> `[1] "123"` | Throws an error if the number of arguments doesn't match specifiers. |
+| `is.numeric()` | Evaluates to TRUE if the variable is of numeric type. | `is.numeric(5)` -> `[1] TRUE` | `is.numeric(NA)` is logical, but `is.numeric(NA_real_)` is TRUE. |
+| `ifelse()` | A shorthand vectorized alternative to the standard if...else statement. | `ifelse(c(1) > 0, "Y", "N")` -> `[1] "Y"` | If the condition evaluates to `NA`, the output element will be `NA`. |
+| `c()` | Combines or concatenates values into a vector. | `c(1, 2)` -> `[1] 1 2` | Mix types (e.g. number + string) and everything becomes strings. |
+| `rep()` | Repeats elements of vectors using 'times' or 'each' arguments. | `rep(2, times=2)` -> `[1] 2 2` | `rep(1, times=0)` returns an empty vector: `numeric(0)`. |
+| `length()` | Finds the number of elements present inside a vector or list. | `length(c(1, 2))` -> `[1] 2` | `length(NULL)` evaluates to `0`. |
+| `list()` | Creates a collection of similar or different types of data. | `list(1, "A")` -> `[[1]] 1 [[2]] "A"` | A list can contain lists inside itself (nested lists). |
+| `append()` | Adds an item at the end of a list or vector. | `append(c(1), 2)` -> `[1] 1 2` | Does not modify the original variable in-place; must reassign. |
+| `factorial()` | Calculates the factorial value of a number or vector. | `factorial(4)` -> `[1] 24` | `factorial(0)` returns `1`. `factorial(-1)` returns `NaN`. |
+| `sum()` | Finds the sum of a sequence of numbers. | `sum(1, 2)` -> `[1] 3` | `sum(c(1, NA))` is `NA`. Use `na.rm=TRUE` to ignore NAs. |
+| `max()` / `min()` | Finds the maximum/minimum value in a sequence of numbers. | `max(4:6)` -> `[1] 6` | `max(numeric(0))` returns `-Inf` and a warning message. |
+| `seq()` | Generates regular sequences (more flexible than the `:` operator). | `seq(1, 5, by=2)` -> `[1] 1 3 5` | `seq(1, 1)` correctly handles start and end being the same. |
+| `mean()` | Calculates the arithmetic mean (average). | `mean(c(2, 4))` -> `[1] 3` | `mean(c(1, NA))` returns `NA`. Requires `na.rm = TRUE`. |
+| `is.na()` | Checks for missing values (`NA`) and returns a logical vector. | `is.na(c(1, NA))` -> `[1] FALSE TRUE` | `is.na(NaN)` also evaluates to `TRUE` in R. |
+| `str()` | Compactly displays the internal structure of an R object. | `str(c(1,2))` -> `num [1:2] 1 2` | Calling `str(NULL)` safely returns ` NULL`. |
+| `typeof()` | Determines the internal R type or storage mode of any object. | `typeof(1L)` -> `[1] "integer"` | `typeof(c(1, 2))` returns `"double"`, while `class` is `"numeric"`. |
+| `rm()` | Removes objects/variables from the current workspace environment. | `rm(x)` -> *(Removes x)* | `rm(list = ls())` completely clears the entire workspace. |
+
+---
+
+## 55 Practice Questions (Basic to Advanced)
+
+Test your knowledge! Click on any question to reveal the answer.
+
+<details>
+<summary><b>Q1: What is the primary difference between `<-` and `=` in R?</b></summary>
+
+> `<-` is the standard assignment operator for variables. `=` is typically used only for assigning values to parameters inside function calls.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q2: Can you assign a variable from right to left in R?</b></summary>
+
+> Yes, R supports rightward assignment using `->` (e.g., `"Hello" -> my_var`).
+
+</details>
+<br>
+
+<details>
+<summary><b>Q3: How do you write a true multi-line comment in R?</b></summary>
+
+> R does not have a native multi-line comment syntax. You must either use `#` on every line or wrap text in a dummy `if (FALSE) { ... }` block.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q4: What is the difference between `class(14)` and `class(14L)`?</b></summary>
+
+> `14` is a floating-point `numeric` by default. The `L` suffix explicitly declares `14L` as an `integer`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q5: Is R case-sensitive? Give an example.</b></summary>
+
+> Yes. `TRUE` is a valid boolean keyword, but `True` or `true` will throw an 'object not found' error.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q6: What happens if you type `T <- FALSE`?</b></summary>
+
+> It will successfully overwrite `T` to mean `FALSE`. This is why using `TRUE`/`FALSE` is safer than the `T`/`F` shorthands, as the full words are reserved and cannot be overwritten.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q7: What is the exact output of `paste("Hello", "R")`?</b></summary>
+
+> `"Hello R"`. The standard `paste()` function adds a single space between items by default.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q8: What is the exact output of `paste0("Hello", "R")`?</b></summary>
+
+> `"HelloR"`. The `paste0()` function explicitly concatenates with no spaces.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q9: If `x <- 12.34`, what does `sprintf("Value: %f", x)` do?</b></summary>
+
+> It formats the float as a string, outputting `"Value: 12.340000"`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q10: Why can't you use `cat()` to print a list?</b></summary>
+
+> `cat()` only works with basic atomic types (logical, integer, numeric, character). It cannot handle complex data structures like lists.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q11: What happens when you run `c(1, "A", TRUE)`?</b></summary>
+
+> R coerces them all to the most flexible type (character). The output is `"1" "A" "TRUE"`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q12: What does `is.numeric(NA)` return?</b></summary>
+
+> `[1] logical`. Standard `NA` is a logical type by default, unless specified as `NA_real_`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q13: How is `ifelse()` different from a standard `if...else` block?</b></summary>
+
+> `ifelse()` is vectorized, meaning it can evaluate an entire vector of conditions at once and return a vector of results. `if...else` evaluates a single condition.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q14: What happens if you pass a vector of length 5 into a standard `if (condition)` statement?</b></summary>
+
+> The `if` statement will only evaluate the very first element of the vector and will throw a warning.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q15: What does the `%%` operator do?</b></summary>
+
+> It calculates the modulo (remainder of division). E.g., `5 %% 2` equals `1`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q16: When does a `while` loop terminate?</b></summary>
+
+> When its test condition evaluates to `FALSE`, or when a `break` statement is encountered inside the loop.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q17: If a `break` statement is executed inside a nested loop, what happens?</b></summary>
+
+> It immediately terminates *only the innermost loop* where the `break` was called. The outer loop continues running.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q18: What does the `next` statement do?</b></summary>
+
+> It immediately skips the rest of the current loop iteration and jumps to the evaluation of the next iteration.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q19: What is the index of the first element in an R vector?</b></summary>
+
+> `1`. Unlike Python or C, R uses 1-based indexing.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q20: What does negative indexing do, e.g., `my_vector[-2]`?</b></summary>
+
+> It returns all elements of the vector *except* the element at index 2.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q21: What is the output of `length(NULL)`?</b></summary>
+
+> It returns `0`, because `NULL` represents an empty, undefined object.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q22: What is the output of `length(NA)`?</b></summary>
+
+> It returns `1`. `NA` represents a single missing value, so it still takes up one slot in memory.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q23: What is the difference between `1:3` and `c(1, 2, 3)`?</b></summary>
+
+> Practically nothing in the output, but `:` is a sequence generator operator that efficiently creates the integer sequence without explicitly typing each element.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q24: What is the output of `rep(c(1, 2), times = 2)`?</b></summary>
+
+> `1 2 1 2`. It repeats the entire sequence twice.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q25: What is the output of `rep(c(1, 2), each = 2)`?</b></summary>
+
+> `1 1 2 2`. It repeats each individual element twice before moving to the next.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q26: How do you permanently change the 2nd element of `x` to 5?</b></summary>
+
+> `x[2] <- 5`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q27: What is the fundamental difference between a Vector and a List?</b></summary>
+
+> A vector can only hold elements of the *same* data type. A list can hold elements of *different* data types (strings, numbers, booleans, or even other lists).
+
+</details>
+<br>
+
+<details>
+<summary><b>Q28: Does `append(my_list, 5)` permanently change `my_list`?</b></summary>
+
+> No. Most functions in R do not modify in-place. You must overwrite the variable: `my_list <- append(my_list, 5)`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q29: How do you extract the actual value of the first element in a list, not just a sub-list?</b></summary>
+
+> Using double brackets: `my_list[[1]]`. Single brackets `my_list[1]` return a new list containing that element.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q30: What keyword is used to create a custom function?</b></summary>
+
+> `function()`. Example: `my_func <- function(x) { ... }`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q31: What is a formal argument vs an actual argument?</b></summary>
+
+> Formal arguments are the parameters defined inside the `function()` parentheses. Actual arguments are the actual values passed when the function is called.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q32: Can you change the order of arguments when calling a function?</b></summary>
+
+> Yes, by using named arguments (e.g., `power(b=3, a=2)`).
+
+</details>
+<br>
+
+<details>
+<summary><b>Q33: How do you give a parameter a default value?</b></summary>
+
+> By assigning it in the function definition: `my_func <- function(length = 5) { ... }`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q34: If an R function doesn't use the `return()` statement, what does it return?</b></summary>
+
+> It implicitly returns the result of the very last evaluated expression in the function body.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q35: What is nested function calling?</b></summary>
+
+> Passing the result of one function directly as an argument into another function. E.g., `print(sum(1, 2))`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q36: What is 'Lazy Evaluation' in R?</b></summary>
+
+> R only evaluates function arguments when they are actually needed inside the function body.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q37: If a function is defined as `f <- function(a, b) { print(a) }`, what happens if you call `f(5)` without providing `b`?</b></summary>
+
+> It successfully prints `5`. Because `b` is never used in the function, R's lazy evaluation ignores the missing argument.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q38: Following the previous question, what happens if the function *does* use `b` later, e.g., `print(a + b)`?</b></summary>
+
+> R will throw an error only at the exact moment it tries to evaluate `b` and realizes it is missing.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q39: What is an inline function?</b></summary>
+
+> A compact function written on a single line, often without braces. E.g., `f <- function(x) x^2`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q40: What is the output of `sum(4:6)`?</b></summary>
+
+> `15` (because 4 + 5 + 6 = 15).
+
+</details>
+<br>
+
+<details>
+<summary><b>Q41: What happens if you sum a vector containing an `NA`, like `sum(c(1, 2, NA))`?</b></summary>
+
+> The result is `NA`. You must use the argument `na.rm = TRUE` to ignore missing values.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q42: What does `Inf` signify?</b></summary>
+
+> Positive Infinity, typically resulting from mathematical operations like dividing a positive number by 0.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q43: What is the difference between `NaN` and `NA`?</b></summary>
+
+> `NaN` is 'Not a Number' (a mathematical impossibility like `0/0`). `NA` is a logical placeholder for missing data.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q44: Is `NaN` considered an `NA`?</b></summary>
+
+> Yes, `is.na(NaN)` returns `TRUE`. However, `is.nan(NA)` returns `FALSE`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q45: If `x <- c(1, 2, 3)`, what does `str(x)` do?</b></summary>
+
+> It displays the compact internal structure of the object: `num [1:3] 1 2 3`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q46: What does `rm(x)` do?</b></summary>
+
+> It removes the variable `x` from the current workspace environment, freeing up memory.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q47: How do you access the documentation/help file for the `sum` function?</b></summary>
+
+> Type `help(sum)` or `?sum` in the console.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q48: How do you search for help regarding operators like `+` or reserved keywords like `if`?</b></summary>
+
+> You must wrap them in backticks or quotes: `help("+")` or `?"if"`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q49: What does `&` do vs `|` in R?</b></summary>
+
+> `&` is the logical AND operator (returns TRUE only if both sides are TRUE). `|` is the logical OR operator (returns TRUE if at least one side is TRUE).
+
+</details>
+<br>
+
+<details>
+<summary><b>Q50: What does the `!` operator do?</b></summary>
+
+> It is the logical NOT operator. It reverses booleans, turning `TRUE` to `FALSE` and vice versa.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q51: What is the rule for starting a variable name with a period (.)?</b></summary>
+
+> A variable name can start with a period, but it CANNOT be followed immediately by a digit (e.g., `.myvar` is valid, `.2var` is invalid).
+
+</details>
+<br>
+
+<details>
+<summary><b>Q52: What is a Boolean shorthand in R?</b></summary>
+
+> You can type `T` or `F` instead of typing out `TRUE` or `FALSE`.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q53: Are single characters (like "a") and strings (like "Word") considered different classes in R?</b></summary>
+
+> No, they both belong to the `character` class. R does not have a separate 'char' type like C or Java.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q54: What does `%c`, `%e`, and `%u` do in the `sprintf()` function?</b></summary>
+
+> `%c` formats as a character, `%e` formats in scientific notation, and `%u` formats as an unsigned decimal integer.
+
+</details>
+<br>
+
+<details>
+<summary><b>Q55: What is a recursive function?</b></summary>
+
+> A function that calls itself from within its own code block (e.g., calculating a factorial mathematically).
+
+</details>
+<br>
+
diff --git a/docs/index.html b/docs/index.html
@@ -861,6 +861,157 @@ left <- "R is fun"
</div>
<div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
+ <div class="flex items-center gap-2.5 min-w-0 cursor-pointer flex-1" onclick="showCode('code-Semester_1-R-Code-R_Code-10-r', 'R_Code-10.r', 'https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-10.r')">
+ <svg class="w-4 h-4 text-slate-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+ <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+ </svg>
+ <span class="text-sm text-slate-600 font-medium group-hover:text-blue-600 truncate">R_Code-10.r</span>
+ </div>
+ <div class="flex items-center gap-2 opacity-0 group-hover:opacity-100 transition-opacity">
+ <a href="https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-10.r" target="_blank" class="p-1.5 text-slate-400 hover:text-slate-700 hover:bg-slate-100 rounded-md" title="View on GitHub">
+ <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 24 24"><path fill-rule="evenodd" d="M12 2C6.477 2 2 6.484 2 12.017c0 4.425 2.865 8.18 6.839 9.504.5.092.682-.217.682-.483 0-.237-.008-.868-.013-1.703-2.782.605-3.369-1.343-3.369-1.343-.454-1.158-1.11-1.466-1.11-1.466-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-2.126 1.029-2.935-.103-.253-.446-1.372.097-2.897 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0112 6.844c.85.004 1.705.115 2.504.337 1.909-1.296 2.747-1.027 2.747-1.027.546 1.525.202 2.644.1 2.897.64.809 1.026 1.841 1.026 2.935 0 3.847-2.337 4.687-4.565 4.935.359.309.678.92.678 1.855 0 1.338-.012 2.419-.012 2.747 0 .268.18.58.688.482A10.019 10.019 0 0022 12.017C22 6.484 17.522 2 12 2z" clip-rule="evenodd"></path></svg>
+ </a>
+ </div>
+ <!-- Embedded Code Storage -->
+ <div id="code-Semester_1-R-Code-R_Code-10-r" style="display:none;"># Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Create a numeric vector of student exam scores.
+# Write a single line of code that evaluates these scores and
+# outputs "Pass" for any score 50 or above, and "Fail" for any score below 50.
+
+score <- c(45, 26, 89, 21, 75, 99, 13, 68, 85)
+
+ifelse(score < 50, "Fail", "Pass")</div>
+ </div>
+
+ <div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
+ <div class="flex items-center gap-2.5 min-w-0 cursor-pointer flex-1" onclick="showCode('code-Semester_1-R-Code-R_Code-11-r', 'R_Code-11.r', 'https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-11.r')">
+ <svg class="w-4 h-4 text-slate-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+ <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+ </svg>
+ <span class="text-sm text-slate-600 font-medium group-hover:text-blue-600 truncate">R_Code-11.r</span>
+ </div>
+ <div class="flex items-center gap-2 opacity-0 group-hover:opacity-100 transition-opacity">
+ <a href="https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-11.r" target="_blank" class="p-1.5 text-slate-400 hover:text-slate-700 hover:bg-slate-100 rounded-md" title="View on GitHub">
+ <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 24 24"><path fill-rule="evenodd" d="M12 2C6.477 2 2 6.484 2 12.017c0 4.425 2.865 8.18 6.839 9.504.5.092.682-.217.682-.483 0-.237-.008-.868-.013-1.703-2.782.605-3.369-1.343-3.369-1.343-.454-1.158-1.11-1.466-1.11-1.466-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-2.126 1.029-2.935-.103-.253-.446-1.372.097-2.897 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0112 6.844c.85.004 1.705.115 2.504.337 1.909-1.296 2.747-1.027 2.747-1.027.546 1.525.202 2.644.1 2.897.64.809 1.026 1.841 1.026 2.935 0 3.847-2.337 4.687-4.565 4.935.359.309.678.92.678 1.855 0 1.338-.012 2.419-.012 2.747 0 .268.18.58.688.482A10.019 10.019 0 0022 12.017C22 6.484 17.522 2 12 2z" clip-rule="evenodd"></path></svg>
+ </a>
+ </div>
+ <!-- Embedded Code Storage -->
+ <div id="code-Semester_1-R-Code-R_Code-11-r" style="display:none;"># Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Write a while loop that starts with a multiplier of 1.
+# The loop should multiply the current multiplier by 4,
+# assign it to a result variable, and print the result.
+# The loop should exit if the result exceeds 100; otherwise,
+# increment the multiplier by 1.
+
+num = 1
+while(TRUE) {
+ result <- num * 4
+ print(result)
+
+ if (result > 100) {
+ break
+ }
+ num = num + 1
+}
+</div>
+ </div>
+
+ <div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
+ <div class="flex items-center gap-2.5 min-w-0 cursor-pointer flex-1" onclick="showCode('code-Semester_1-R-Code-R_Code-12-r', 'R_Code-12.r', 'https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-12.r')">
+ <svg class="w-4 h-4 text-slate-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+ <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+ </svg>
+ <span class="text-sm text-slate-600 font-medium group-hover:text-blue-600 truncate">R_Code-12.r</span>
+ </div>
+ <div class="flex items-center gap-2 opacity-0 group-hover:opacity-100 transition-opacity">
+ <a href="https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-12.r" target="_blank" class="p-1.5 text-slate-400 hover:text-slate-700 hover:bg-slate-100 rounded-md" title="View on GitHub">
+ <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 24 24"><path fill-rule="evenodd" d="M12 2C6.477 2 2 6.484 2 12.017c0 4.425 2.865 8.18 6.839 9.504.5.092.682-.217.682-.483 0-.237-.008-.868-.013-1.703-2.782.605-3.369-1.343-3.369-1.343-.454-1.158-1.11-1.466-1.11-1.466-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-2.126 1.029-2.935-.103-.253-.446-1.372.097-2.897 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0112 6.844c.85.004 1.705.115 2.504.337 1.909-1.296 2.747-1.027 2.747-1.027.546 1.525.202 2.644.1 2.897.64.809 1.026 1.841 1.026 2.935 0 3.847-2.337 4.687-4.565 4.935.359.309.678.92.678 1.855 0 1.338-.012 2.419-.012 2.747 0 .268.18.58.688.482A10.019 10.019 0 0022 12.017C22 6.484 17.522 2 12 2z" clip-rule="evenodd"></path></svg>
+ </a>
+ </div>
+ <!-- Embedded Code Storage -->
+ <div id="code-Semester_1-R-Code-R_Code-12-r" style="display:none;"># Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Write a custom function named calculate_area that takes
+# two parameters: length and width. The width parameter should have
+# a default value of 5. The function should print the product of the
+# two parameters. Finally, call your function passing only the value 12 for the length.
+
+calculate_area <- function(length, width = 5) {
+ print(length * width)
+}
+
+calculate_area(12)</div>
+ </div>
+
+ <div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
+ <div class="flex items-center gap-2.5 min-w-0 cursor-pointer flex-1" onclick="showCode('code-Semester_1-R-Code-R_Code-13-r', 'R_Code-13.r', 'https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-13.r')">
+ <svg class="w-4 h-4 text-slate-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+ <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+ </svg>
+ <span class="text-sm text-slate-600 font-medium group-hover:text-blue-600 truncate">R_Code-13.r</span>
+ </div>
+ <div class="flex items-center gap-2 opacity-0 group-hover:opacity-100 transition-opacity">
+ <a href="https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-13.r" target="_blank" class="p-1.5 text-slate-400 hover:text-slate-700 hover:bg-slate-100 rounded-md" title="View on GitHub">
+ <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 24 24"><path fill-rule="evenodd" d="M12 2C6.477 2 2 6.484 2 12.017c0 4.425 2.865 8.18 6.839 9.504.5.092.682-.217.682-.483 0-.237-.008-.868-.013-1.703-2.782.605-3.369-1.343-3.369-1.343-.454-1.158-1.11-1.466-1.11-1.466-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-2.126 1.029-2.935-.103-.253-.446-1.372.097-2.897 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0112 6.844c.85.004 1.705.115 2.504.337 1.909-1.296 2.747-1.027 2.747-1.027.546 1.525.202 2.644.1 2.897.64.809 1.026 1.841 1.026 2.935 0 3.847-2.337 4.687-4.565 4.935.359.309.678.92.678 1.855 0 1.338-.012 2.419-.012 2.747 0 .268.18.58.688.482A10.019 10.019 0 0022 12.017C22 6.484 17.522 2 12 2z" clip-rule="evenodd"></path></svg>
+ </a>
+ </div>
+ <!-- Embedded Code Storage -->
+ <div id="code-Semester_1-R-Code-R_Code-13-r" style="display:none;"># Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Create a list named student_record containing a string,
+# an integer, and a numeric vector of two grades. Then, add the
+# logical value TRUE to the end of the list, ensuring the original
+# student_record variable is updated. Print the final list.
+
+student_record <- list("Amit Dutta", 95, c(95, 96))
+print(student_record)
+student_record <- append(student_record, TRUE)
+print(student_record)</div>
+ </div>
+
+ <div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
+ <div class="flex items-center gap-2.5 min-w-0 cursor-pointer flex-1" onclick="showCode('code-Semester_1-R-Code-R_Code-14-r', 'R_Code-14.r', 'https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-14.r')">
+ <svg class="w-4 h-4 text-slate-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+ <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+ </svg>
+ <span class="text-sm text-slate-600 font-medium group-hover:text-blue-600 truncate">R_Code-14.r</span>
+ </div>
+ <div class="flex items-center gap-2 opacity-0 group-hover:opacity-100 transition-opacity">
+ <a href="https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-14.r" target="_blank" class="p-1.5 text-slate-400 hover:text-slate-700 hover:bg-slate-100 rounded-md" title="View on GitHub">
+ <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 24 24"><path fill-rule="evenodd" d="M12 2C6.477 2 2 6.484 2 12.017c0 4.425 2.865 8.18 6.839 9.504.5.092.682-.217.682-.483 0-.237-.008-.868-.013-1.703-2.782.605-3.369-1.343-3.369-1.343-.454-1.158-1.11-1.466-1.11-1.466-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-2.126 1.029-2.935-.103-.253-.446-1.372.097-2.897 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0112 6.844c.85.004 1.705.115 2.504.337 1.909-1.296 2.747-1.027 2.747-1.027.546 1.525.202 2.644.1 2.897.64.809 1.026 1.841 1.026 2.935 0 3.847-2.337 4.687-4.565 4.935.359.309.678.92.678 1.855 0 1.338-.012 2.419-.012 2.747 0 .268.18.58.688.482A10.019 10.019 0 0022 12.017C22 6.484 17.522 2 12 2z" clip-rule="evenodd"></path></svg>
+ </a>
+ </div>
+ <!-- Embedded Code Storage -->
+ <div id="code-Semester_1-R-Code-R_Code-14-r" style="display:none;"># Author: Amit Dutta (amitdutta4255@gmail.com) | Date: 20 Mar 2026
+# Repo: https://github.com/notamitgamer/bsc
+# License: MIT
+
+# Write an if...else if...else block that evaluates a newly created temperature variable.
+# * If the temperature is strictly greater than 30, print: "30+ is too hot!"
+# * If the temperature is between 20 and 30 (inclusive), print: "Perfect weather."
+# * Otherwise, print: "It is quite cold."
+
+temperature <- 29
+if(temperature > 30) {
+ print("30+ is too hot!")
+} else if(temperature >= 20 && temperature <= 30) {
+ print("Perfect weather")
+} else {
+ print("It is quite cold.")
+}</div>
+ </div>
+
+ <div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
<div class="flex items-center gap-2.5 min-w-0 cursor-pointer flex-1" onclick="showCode('code-Semester_1-R-Code-R_Code-2-r', 'R_Code-2.r', 'https://github.com/notamitgamer/bsc/blob/main/Semester_1/R/Code/R_Code-2.r')">
<svg class="w-4 h-4 text-slate-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
<path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
@@ -1022,7 +1173,9 @@ list1 <- list(24L, "Sabby", 5.4, "Nepal")
print("Before update")
print(list1)
print("After Update")
-append(list1, 3.14)</div>
+list1 <- append(list1, 3.14)
+print(list1)
+</div>
</div>
<div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
@@ -1046,12 +1199,13 @@ append(list1, 3.14)</div>
# a and b. Give a a default value of 2. The function should print the result
# of a raised to the power of b (a^b).
-power <- function (a, b) {
+power <- function (a = 2, b) {
return (a^b)
}
a <- 2
b <- 3
-print(power(a, b))</div>
+print(power(a, b))
+print(power("b" = b))</div>
</div>
<div class="file-item flex items-center justify-between px-3 py-2 hover:bg-white hover:shadow-sm rounded-lg transition-all group border border-transparent hover:border-slate-100 mb-1">
