Find position of a Matched Pattern in a String in R Programming – grep() Function

grep() function in R Language is used to search for matches of a pattern within each element of the given string.

Syntax:
grep(pattern, x, ignore.case=TRUE/FALSE, value=TRUE/FALSE)
Parameters:
pattern: Specified pattern which is going to be matched with given elements of the string. 
x: Specified string vector. 
ignore.case: If its value is TRUE, it ignores case. 
value: If its value is TRUE, it return the matching elements vector, else return the indices vector. 

Example 1:

Python3

# R program to illustrate
# grep function

# Creating string vector
x <- c("GFG", "gfg", "Geeks", "GEEKS")

# Calling grep() function
grep("gfg", x)
grep("Geeks", x)
grep("gfg", x, ignore.case = FALSE)
grep("Geeks", x, ignore.case = TRUE)

Output :

[1] 2
[1] 3
[1] 2
[1] 3 4

Example 2:

Python3

# R program to illustrate
# grep function

# Creating string vector
x <- c("GFG", "gfg", "Geeks", "GEEKS")

# Calling grep() function
grep("gfg", x, ignore.case = TRUE, value = TRUE)
grep("G", x, ignore.case = TRUE, value = TRUE)
grep("Geeks", x, ignore.case = FALSE, value = FALSE)
grep("GEEKS", x, ignore.case = FALSE, value = FALSE)

Output:

[1] "GFG" "gfg"
[1] "GFG"   "gfg"   "Geeks" "GEEKS"
[1] 3
[1] 4