Check for a Pattern in the Vector in R Programming - grepl() Function

Last Updated : 15 Jul, 2025
grepl() function in R Language is used to return the value True if the specified pattern is found in the vector and false if it is not found.
Syntax: grepl(pattern, string, ignore.case=FALSE) Parameters: pattern: regular expressions pattern string: character vector to be searched ignore.case: whether to ignore case in the search. Here ignore.case is an optional parameter as is set to FALSE by default.
Example 1: Python3 
# R program to illustrate
# grepl function

# Initializing a character vector
str <- c("GFG", "gfg", "Geek", "Geeks") 

# Calling the grepl() function to
# find whether any instance(s) of
# ‘GF’ and 'G' are present in the string
grepl('GF', str, ignore.case ="True") 
grepl('G', str, ignore.case ="True")
Output: 
[1]  TRUE  TRUE FALSE FALSE
[1] TRUE TRUE TRUE TRUE
Example 2: Python3 
# R program to illustrate
# grepl function

# Initializing a character vector
str <- c("GFG", "gfg", "Geek", "Geeks") 

# Calling the grepl() function to
# find whether any instance(s) of
# ‘gfg’ and 'Geek' are present in the string
grepl('gfg', str) 
grepl('Geek', str)
Output: 
[1] FALSE  TRUE FALSE FALSE
[1] FALSE FALSE  TRUE  TRUE
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