Remove everything after space in string

r regex gsub
user1214864 picture user1214864 · Feb 16, 2012 · Viewed 30.3k times · Source

I would like to remove everything after a space in a string.

For example:

"my string is sad"

should return 

"my"

I've been trying to figure out how to do this using sub/gsub but have been unsuccessful so far.

Answer

Wiktor Stribiżew picture Wiktor Stribiżew · Feb 12, 2018

You may use a regex like

sub(" .*", "", x)

See the regex demo.

Here, sub will only perform a single search and replace operation, the .* pattern will find the first space (since the regex engine is searching strings from left to right) and .* matches any zero or more characters (in TRE regex flavor, even including line break chars, beware when using perl=TRUE, then it is not the case) as many as possible, up to the string end.

Some variations:

sub("[[:space:]].*", "", x) # \s or [[:space:]] will match more whitespace chars
sub("(*UCP)(?s)\\s.*", "", x, perl=TRUE) # PCRE Unicode-aware regex
stringr::str_replace(x, "(?s) .*", "")   # (?s) will force . to match any chars

See the online R demo.

Related questions

Replace specific characters within strings

I would like to remove specific characters from strings within a vector, similar to the Find and Replace feature in Excel. Here are the data I start with: group <- data.frame(c("12357e", "12575e", "197e18", "e18947") I start …

Read More
gsub() in R is not replacing '.' (dot)

I want to replace dots in "2014.06.09" to "2014-06-09". I am using gsub() function for it. If x <- "2014.06.09" gsub('2', '-' ,x) # [1] "-014.06.09" But when I try gsub('.', '-', x) # [1] "----------" instead of "2014-06-09". …

Read More
How to remove specific special characters in R

I have some sentences like this one. c = "In Acid-base reaction (page[4]), why does it create water and not H+?" I want to remove all special characters except for '?&+-/ I know that if I want to remove …

Read More