How to remove all whitespace from a string?

So " xx yy 11 22 33 " will beco开发者_StackOverflow社区me "xxyy112233". How can I achieve this?

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In general, we want a solution that is vectorised, so here's a better test example:

whitespace <- " \t\n\r\v\f" # space, tab, newline, 
                            # carriage return, vertical tab, form feed
x <- c(
  " x y ",           # spaces before, after and in between
  " \u2190 \u2192 ", # contains unicode chars
  paste0(            # varied whitespace     
    whitespace, 
    "x", 
    whitespace, 
    "y", 
    whitespace, 
    collapse = ""
  ),   
  NA                 # missing
)
## [1] " x y "                           
## [2] " ← → "                           
## [3] " \t\n\r\v\fx \t\n\r\v\fy \t\n\r\v\f"
## [4] NA

---

The base R approach: gsub

gsub replaces all instances of a string (fixed = TRUE) or regular expression (fixed = FALSE, the default) with another string. To remove all spaces, use:

gsub(" ", "", x, fixed = TRUE)
## [1] "xy"                            "←→"             
## [3] "\t\n\r\v\fx\t\n\r\v\fy\t\n\r\v\f" NA 

As DWin noted, in this case fixed = TRUE isn't necessary but provides slightly better performance since matching a fixed string is faster than matching a regular expression.

If you want to remove all types of whitespace, use:

gsub("[[:space:]]", "", x) # note the double square brackets
## [1] "xy" "←→" "xy" NA 

gsub("\\s", "", x)         # same; note the double backslash

library(regex)
gsub(space(), "", x)       # same

"[:space:]" is an R-specific regular expression group matching all space characters. \s is a language-independent regular-expression that does the same thing.

---

The stringr approach: str_replace_all and str_trim

stringr provides more human-readable wrappers around the base R functions (though as of Dec 2014, the development version has a branch built on top of stringi, mentioned below). The equivalents of the above commands, using [str_replace_all][3], are:

library(stringr)
str_replace_all(x, fixed(" "), "")
str_replace_all(x, space(), "")

stringr also has a str_trim function which removes only leading and trailing whitespace.

str_trim(x) 
## [1] "x y"          "← →"          "x \t\n\r\v\fy" NA    
str_trim(x, "left")    
## [1] "x y "                   "← → "    
## [3] "x \t\n\r\v\fy \t\n\r\v\f" NA     
str_trim(x, "right")    
## [1] " x y"                   " ← →"    
## [3] " \t\n\r\v\fx \t\n\r\v\fy" NA      

---

The stringi approach: stri_replace_all_charclass and stri_trim

stringi is built upon the platform-independent ICU library, and has an extensive set of string manipulation functions. The equivalents of the above are:

library(stringi)
stri_replace_all_fixed(x, " ", "")
stri_replace_all_charclass(x, "\\p{WHITE_SPACE}", "")

Here "\\p{WHITE_SPACE}" is an alternate syntax for the set of Unicode code points considered to be whitespace, equivalent to "[[:space:]]", "\\s" and space(). For more complex regular expression replacements, there is also stri_replace_all_regex.

stringi also has trim functions.

stri_trim(x)
stri_trim_both(x)    # same
stri_trim(x, "left")
stri_trim_left(x)    # same
stri_trim(x, "right")  
stri_trim_right(x)   # same

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I just learned about the "stringr" package to remove white space from the beginning and end of a string with str_trim( , side="both") but it also has a replacement function so that:

a <- " xx yy 11 22 33 " 
str_replace_all(string=a, pattern=" ", repl="")

[1] "xxyy112233"

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x = "xx yy 11 22 33"

gsub(" ", "", x)

> [1] "xxyy112233"

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Use [[:blank:]] to match any kind of horizontal white_space characters.

gsub("[[:blank:]]", "", " xx yy 11 22  33 ")
# [1] "xxyy112233"

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Please note that soultions written above removes only space. If you want also to remove tab or new line use stri_replace_all_charclass from stringi package.

library(stringi)
stri_replace_all_charclass("   ala \t  ma \n kota  ", "\\p{WHITE_SPACE}", "")
## [1] "alamakota"

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The function str_squish() from package stringr of tidyverse does the magic!

library(dplyr)
library(stringr)

df <- data.frame(a = c("  aZe  aze s", "wxc  s     aze   "), 
                 b = c("  12    12 ", "34e e4  "), 
                 stringsAsFactors = FALSE)
df <- df %>%
  rowwise() %>%
  mutate_all(funs(str_squish(.))) %>%
  ungroup()
df

# A tibble: 2 x 2
  a         b     
  <chr>     <chr> 
1 aZe aze s 12 12 
2 wxc s aze 34e e4

---

Another approach can be taken into account

library(stringr)
str_replace_all(" xx yy 11 22  33 ", regex("\\s*"), "")

#[1] "xxyy112233"

\\s: Matches Space, tab, vertical tab, newline, form feed, carriage return

*: Matches at least 0 times

---

income<-c("$98,000.00 ", "$90,000.00 ", "$18,000.00 ", "")

To remove space after .00 use the trimws() function.

income<-trimws(income)

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From stringr library you could try this:

1. Remove consecutive fill blanks

2. Remove fill blank

   library(stringr)

               2.         1.
               |          |
               V          V
   
       str_replace_all(str_trim(" xx yy 11 22  33 "), " ", "")