Removing spaces from a variable input using PowerShell 4.0

Question

I've tried a few things already but they don't seem to work for some reason.

Basically what I'm attempting to do is have a user input a value using the "Read-host" cmdlet, then strip it of any spaces.

I tried:

$answer = read-host
$answer.replace(' ' , '""')

And:

$answer = read-host
$answer -replace (' ')

I'm probably missing something really obvious, but if anyone could help me out or show me an easier way to achieve this I would appreciate it.

I was going to pipeline the variable to a command and strip it in that fashion, but none of the examples I've seen work, although they look much easier.

$str = $str.replace(' ','')

Kellen Stuart
– Kellen Stuart

2017-05-15 18:27:08 +00:00
Commented May 15, 2017 at 18:27 — Kellen Stuart
– Kellen Stuart, Commented May 15, 2017 at 18:27

Logan · Accepted Answer · 2017-01-21 02:06:30Z

84

The Replace operator means Replace something with something else; do not be confused with removal functionality.

Also you should send the result processed by the operator to a variable or to another operator. Neither .Replace(), nor -replace modifies the original variable.

To remove all spaces, use 'Replace any space symbol with empty string'

$string = $string -replace '\s',''

To remove all spaces at the beginning and end of the line, and replace all double-and-more-spaces or tab symbols to spacebar symbol, use

$string = $string -replace '(^\s+|\s+$)','' -replace '\s+',' '

or the more native System.String method

$string = $string.Trim()

Regexp is preferred, because ' ' means only 'spacebar' symbol, and '\s' means 'spacebar, tab and other space symbols'. Note that $string.Replace() does 'Normal' replace, and $string -replace does RegEx replace, which is more heavy but more functional.

Note that RegEx have some special symbols like dot (.), braces ([]()), slashes (\), hats (^), mathematical signs (+-) or dollar signs ($) that need do be escaped. ( 'my.space.com' -replace '\.','-' => 'my-space-com'. A dollar sign with a number (ex $1) must be used on a right part with care

'2033' -replace '(\d+)',$( 'Data: $1')
Data: 2033

UPDATE: You can also use $str = $str.Trim(), along with TrimEnd() and TrimStart(). Read more at System.String MSDN page.

edited Jan 21, 2017 at 2:06

Logan

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answered Jun 22, 2014 at 22:19

filimonic

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1 Comment

Timo Over a year ago

The answer can be confusing for a student/learner because you refer to other replaces besides whitespace.

Kohlbrr · Accepted Answer · 2014-06-22 21:16:03Z

9

You're close. You can strip the whitespace by using the replace method like this:

$answer.replace(' ','')

There needs to be no space or characters between the second set of quotes in the replace method (replacing the whitespace with nothing).

answered Jun 22, 2014 at 21:16

Kohlbrr

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Comments

StephenP · Accepted Answer · 2014-06-23 03:29:17Z

You also have the Trim, TrimEnd and TrimStart methods of the System.String class. The trim method will strip whitespace (with a couple of Unicode quirks) from the leading and trailing portion of the string while allowing you to optionally specify the characters to remove.

#Note there are spaces at the beginning and end
Write-Host " ! This is a test string !%^ "
 ! This is a test string !%^
#Strips standard whitespace
Write-Host " ! This is a test string !%^ ".Trim()
! This is a test string !%^
#Strips the characters I specified
Write-Host " ! This is a test string !%^ ".Trim('!',' ')
This is a test string !%^
#Now removing ^ as well
Write-Host " ! This is a test string !%^ ".Trim('!',' ','^')
This is a test string !%
Write-Host " ! This is a test string !%^ ".Trim('!',' ','^','%')
This is a test string
#Powershell even casts strings to character arrays for you
Write-Host " ! This is a test string !%^ ".Trim('! ^%')
This is a test string

TrimStart and TrimEnd work the same way just only trimming the start or end of the string.

Lee · Accepted Answer · 2014-06-22 21:16:48Z

5

You can use:

$answer.replace(' ' , '')

or

$answer -replace " ", ""

if you want to remove all whitespace you can use:

$answer -replace "\s", ""

answered Jun 22, 2014 at 21:16

Lee

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3 Comments

Timo Over a year ago

What is the diff between \s and ' ' (first and third example)?

Lee Over a year ago

@Timo - ' ' is a string containing a single space so only that character will be matched. "\s" is a regex matching any whitespace so the third example removes all whitespace and not just spaces.

Timo Over a year ago

Thanks Lee so \s is much saver to remove all spaces than ' ' because you can easily type 2 spaces while your intent was just one.

David · Accepted Answer · 2018-06-06 03:20:47Z

1

If the string is

$STR = 'HELLO WORLD'

and you want to remove the empty space between 'HELLO' and 'WORLD'

$STR.replace(' ','')

replace takes the string and replaces white space with empty string (of length 0), in other words the white space is just deleted.

edited Jun 6, 2018 at 3:20

David

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answered Jun 6, 2018 at 1:24

Abs

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