How to remove whitespaces at the beginning of character using regexes in R?

Question

Does anyone know how to remove whitespaces at the beggining of those characters using regexes in R?

 c( "bundesliga" ,                                                                                                                                                                                                              
" liga niemiecka"  ,                                                                                                                                                                                                                          
"   wyniki na żywo" )

This doesn't seem to work:

lowered <- c( "bundesliga" , " liga niemiecka", "   wyniki na żywo" )
grep( x = lowered, pattern = "^\\s*(?=\\S)", value = TRUE, perl = TRUE )

   [1] "bundesliga"        " liga niemiecka"   "   wyniki na żywo"

`str_trim` from `library(stringr)` is a convenient function to use here. `str_trim(v1)` — akrun, Mar 11 '15 at 10:30
If you are using `read.table` (or any `read.xxx`), you may set `strip.white = TRUE` - "allows the stripping of leading and trailing white space from unquoted character fields" — Henrik, Mar 11 '15 at 12:06

score 3 · Accepted Answer · answered Mar 11 '15 at 10:24

3

You can use gsub:

gsub("^\\s*", "", c( "bundesliga", " liga niemiecka", "   wyniki na żywo"))
#[1] "bundesliga"     "liga niemiecka" "wyniki na zywo"

answered Mar 11 '15 at 10:24

Cath

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score 1 · Answer 2 · answered Mar 11 '15 at 10:20

1

^\s*(?=\S)

This should do it.Replace by empty string.

or

^\\s*(?=\\S) for r

answered Mar 11 '15 at 10:20

vks

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lowered <- c( "bundesliga" , " liga niemiecka", " wyniki na żywo" ) grep( x = lowered, pattern = "^\\s*(?=\\S)", value = TRUE ) – Marcin Mar 11 '15 at 10:27
@MarcinKosinski use `perl=True` option too – vks Mar 11 '15 at 10:27
Added this option but still does not work – Marcin Mar 11 '15 at 10:29
1

@MarcinKosinski if you are using `grep` use `gsub` – vks Mar 11 '15 at 10:31

How to remove whitespaces at the beginning of character using regexes in R?

2 Answers2