R Program to Extract Columns From a Dataframe
Selects specific columns.
Program (R)
df <- data.frame(name=c("Ann","Bob"), age=c(19,21))
print(df[, c("name")])Expected Output
name 1 Ann 2 Bob
String Handling and Text Processing in R
Key takeaway: Practice R with 53+ runnable code examples — vectors, strings, math, data frames, recursion, and sampling — with expected output to verify instantly.
R is a programming language for statistical computing and data analysis. These examples are for data science students, researchers, analysts, and anyone learning R for coursework or work projects.
Last updated: October 2026 · 53 examples · All platforms
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- Select a topic from the sidebar or mobile menu
- Study the code and expected output
- Run instantly in our Online R Compiler & Editor or paste into RStudio
- Modify inputs to experiment and learn
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R "Hello World" Program
Prints a greeting using base R.
Program (R)
print("Hello, World!")Expected Output
[1] "Hello, World!"
R Program to Take Input From User
Reads a value from console using readline and prints it.
Program (R)
name <- readline(prompt = "Enter your name: ")
cat("You entered:", name, "\n")Expected Output
Enter your name: Alice You entered: Alice
R Program to Concatenate Two Strings
Concatenates strings using paste0.
Program (R)
a <- "Hello" b <- "World" print(paste0(a, " ", b))
Expected Output
[1] "Hello World"
R Program to Find the Length of a String
Returns character count using nchar.
Program (R)
print(nchar("R language"))Expected Output
[1] 10
R Program to Check if Characters are Present in a String
Checks presence using grepl.
Program (R)
s <- "Hello World"
print(grepl("World", s))Expected Output
[1] TRUE
R Program to Extract n Characters From a String
Extracts a substring using substr.
Program (R)
s <- "Programiz" print(substr(s, 1, 7))
Expected Output
[1] "Program"
R Program to Replace Characters in a String
Replaces matching characters using gsub.
Program (R)
s <- "hello"
print(gsub("l", "x", s))Expected Output
[1] "hexxo"
R Program to Compare two Strings
Compares strings lexically ignoring case.
Program (R)
a <- "Apple"; b <- "apple" print(tolower(a) == tolower(b))
Expected Output
[1] TRUE
R Program to Convert Factors to Characters
Converts a factor vector to character.
Program (R)
f <- factor(c("a", "b", "a"))
print(as.character(f))Expected Output
[1] "a" "b" "a"
R Program to Concatenate a Vector of Strings
Concatenates using paste with collapse.
Program (R)
v <- c("a", "b", "c")
print(paste(v, collapse = ","))Expected Output
[1] "a,b,c"
R Program to Trim Leading and Trailing Whitespaces
Trims spaces using trimws.
Program (R)
s <- " Hello World " print(trimws(s))
Expected Output
[1] "Hello World"
Frequently Asked Questions
Use Rscript from your terminal. Install R from CRAN, save as
main.R, run Rscript main.R. Or use RStudio. No, base R only. All examples use built-in functions for maximum portability.
Yes, absolutely. Copy, tweak inputs, observe outputs — experimentation is the fastest way to learn.
Yes, fully cross-platform. R runs on Windows, macOS, and Linux. Works with R 3.6+.
Learn R the Practical Way
R ranks among the top 20 languages on the TIOBE Index, dominant in academia and data science.
Topics Covered
- Vectors, lists, and data frames
- String manipulation and text processing
- Math, statistics, and random sampling
- Control flow — if/else, for, while
- Recursion and custom functions
- File I/O and formatted output
Who Is This For?
- Data science students — coursework and R-based exams
- Researchers — statistical analysis for papers
- Analysts — data wrangling skills for work
- Career switchers — transitioning into data roles
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