38
Get-Content $user| Foreach-Object{
   $user = $_.Split('=')
   New-Variable -Name $user[0] -Value $user[1]}

Im trying to work on a script and have it split a text file into an array, splitting the file based on each new line

What should I change the "=" sign to

mklement0
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colbyt
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  • Note that `Get-Content $user` streams the content of file `$user` _line by line_ to the pipeline, which means that each line seen inside the `ForEach-Object` via the automatic `$_` variable by definition contains _no_ newlines anymore. – mklement0 Aug 04 '23 at 12:48

7 Answers7

72

It depends on the exact encoding of the textfile, but [Environment]::NewLine usually does the trick.

"This is `r`na string.".Split([Environment]::NewLine)

Output:

This is

a string.

knrdk
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Ryan Ries
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    This will contain empty elements between each line in the original string. – sinned Mar 12 '18 at 09:31
  • Thank you * 1000! This helped me with dealing with the Message property within Windows Event logs, in particular Sysmon event logs. – Paul Masek Nov 21 '19 at 15:18
  • Struggled across trying out loads of code snippets, but this small pearl worked like a charm! Thank you, @Ryan – Yash Gupta Jun 27 '20 at 17:53
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    To avoid the behavior described by @sinned, we can add use the following Split overload : .Split([Environment]::NewLine, [System.StringSplitOptions]::RemoveEmptyEntries) – P-L Jan 19 '23 at 14:56
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    @P-L Thank you for adding this! I had this same issue several years ago and was looking to remove the empty entries. Last time it took me about an hour to find what you posted. Thanks to your comment this time, it was a breeze. – Johnny Welker Mar 28 '23 at 19:07
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    To elaborate on @sinned's comment: The solution is broken with CRLF (``"`r`n"``) newlines in _Windows PowerShell_, because it treats CR and LF _individually_ as separators, and therefore creates an additional, empty array element for each CRLF sequence encountered. The solution would actually work in _PowerShell (Core) 7+_, because the `.Split()` method now has an overload for a single _string_ as the separator. Fundamentally, however, the solution wouldn't work for Unix-format LF newlines (``"`n"`` only) - which you can easily encounter on Windows too. – mklement0 Aug 04 '23 at 13:25
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    @P-L, note that removing _all_ empty elements may be undesired. A better solution is to avoid the spurious empty elements to begin with, namely with ``-split "`r`n"`` - or better yet, so as to match Unix-format LF-only newlines too, `-split '\r?\n'`. If you then want to eliminate (true) empty elements too, append `-ne ''` – mklement0 Aug 04 '23 at 13:25
31

The problem with the String.Split method is that it splits on each character in the given string. Hence, if the text file has CRLF line separators, you will get empty elements.

Better solution, using the -Split operator.

"This is `r`na string." -Split "`r`n" #[Environment]::NewLine, if you prefer
LCC
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21

You can use the String.Split method to split on CRLF and not end up with the empty elements by using the Split(String[], StringSplitOptions) method overload.

There are a couple different ways you can use this method to do it.

Option 1

$input.Split([string[]]"`r`n", [StringSplitOptions]::None)

This will split on the combined CRLF (Carriage Return and Line Feed) string represented by `r`n. The [StringSplitOptions]::None option will allow the Split method to return empty elements in the array, but there should not be any if all the lines end with a CRLF.

Option 2

$input.Split([Environment]::NewLine, [StringSplitOptions]::RemoveEmptyEntries)

This will split on either a Carriage Return or a Line Feed. So the array will end up with empty elements interspersed with the actual strings. The [StringSplitOptions]::RemoveEmptyEntries option instructs the Split method to not include empty elements.

aphoria
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6

The answers given so far consider only Windows as the running environment. If your script needs to run in a variety of environments (Linux, Mac and Windows), consider using the following snippet:

$lines = $string.Split(
    @("`r`n", "`r", "`n"), 
   [StringSplitOptions]::None)
mklement0
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marko.ristin
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  • Nice. Note that your solution needs tweaking in [_PowerShell (Core) 7+_](https://github.com/PowerShell/PowerShell/blob/master/README.md): to find the right `.Split()` method overload there (as well), place `[string[]]` before ``@("`r`n", "`r", "`n")`` A more concise (though probably slower) alternative is to use `$string -split '\r?\n'` – mklement0 Aug 04 '23 at 13:33
0

There is a simple and unusual way to do this.

$lines = [string[]]$string

This will split $string like:

$string.Split(@("`r`n", "`n"))

This is undocumented at least in docs for Conversions.
Beware, this will not remove empty entries. And it doesn't work for Carriage Return (\r) line ending at least on Windows.
Experimented in Powershell 7.2.

mklement0
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RcINS
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  • A `[string[]]` cast does _not_ perform any splitting - e.g. ``([string[]] "line 1`nline 2").Count`` yields `1`. As an aside: your `.Split()` method call wouldn't work as shown. – mklement0 Aug 04 '23 at 13:39
0

have it split a text file into an array

Note that Get-Content does this by default, i.e. it streams a text file's lines one by one (with any trailing newline removed).

If you capture this stream of lines as an array:

  • If there are two or more lines, PowerShell automatically creates an array (of type [object[]]) for you.

  • If there's only one line, PowerShell captures it as-is, as a [string]; to ensure that even a file with a single line is captured as an array, enclose the Get-Content call in @(...), the array-subexpression operator

Therefore, the following captures the individual lines of file $file in an array (but see the faster alternative below):

# See faster alternative below.
$lines = @(Get-Content $file)

However, if the intent is to capture Get-Content's output in full, it isn't actually necessary to stream the lines by one; the -ReadCount parameter allows reading the file in batches of lines, as arrays of the specified size; -ReadCount 0 reads all lines into an array, and unconditionally creates an array, i.e. also if there's only one line. Therefore, the following is a much faster alternative.

# Faster alternative to the above.
$lines = Get-Content -ReadCount 0 $file

Note that if the multiline input string also has a trailing newline (as you're likely to get if you use Get-Content -Raw to read a )


If your intent is to split a multiline string into an array of individual lines, use PowerShell's -splitoperator:

  • Its regex capabilities make it easy to to match newlines (line breaks) in a cross-platform manner: regex \r?\n matches both Windows-format CRLF newlines (\r\n) and Unix-format LF newlines (\n)

The following example uses a here-string to split a multiline string into lines, and visualizes each resulting line by enclosing it in [...]:

@'
line 1
line 2
line 3
'@ -split '\r?\n' |
   ForEach-Object { "[$_]" } # -> '[line 1]', '[line 2]', '[line 3]'

If you want to avoid an empty final array element resulting from a trailing newline (as you might get if you read a text file as a whole into a string, e.g. with Get-Content -Raw), apply regex \r?\n\z via the -replace operator first:

# Multiline string with trailing newline.
@'
line 1
line 2
line 3

'@ -replace '\r?\n\z' -split '\r?\n' |
   ForEach-Object { "[$_]" } # -> '[line 1]', '[line 2]', '[line 3]'

If you want to filter out empty lines, use the filtering capabilities of PowerShell's comparison operators such as -ne, which return the sub-array of matching elements with an array as the LHS:

# Multiline string with empty lines.
@'
line 1

line 2
line 3

'@ -split '\r?\n' -ne '' |
   ForEach-Object { "[$_]" } # -> '[line 1]', '[line 2]', '[line 3]'

If you want to filter out empty or blank (all-whitespace) lines, you can use the -match operator (which equally has filtering capabilities) with regex \S, which matches any non-whitespace character and therefore only lines that are neither empty nor composed exclusively of whitespace chars.:

# The 2nd line is nonempty, but composed of spaces only
@'
line 1
    
line 2
line 3

'@ -split '\r?\n' -match '\S' |
   ForEach-Object { "[$_]" } # -> '[line 1]', '[line 2]', '[line 3]'
mklement0
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-1

This article also explains a lot about how it works with carriage return and line ends. https://virot.eu/powershell-and-newlines/

having some issues with additional empty lines and such i found the solution to understanding the issue. Excerpt from virot.eu:

So what makes up a new line. Here comes the tricky part, it depends. To understand this we need to go to the line feed the character.

Line feed is the ASCII character 10. It in most programming languages escaped by writing \n, but in powershell it is `n. But Windows is not content with just one character, Windows also uses carriage return which is ASCII character 13. Escaped \r. So what is the difference? Line feed advances the pointer down one row and carriage return returns it to the left side again. If you store a file in Windows by default are linebreaks are stored as first a carriage return and then a line feed (\r\n). When we aren’t using any parameters for the split() command it will split on all white-space characters, that is both carriage return, linefeed, tabs and a few more. This is why we are getting 5 results when there is both carriage return and line feeds.

Paul Fijma
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    A link to a solution is welcome, but please ensure your answer is useful without it: [add context around the link](//meta.stackexchange.com/a/8259) so your fellow users will have some idea what it is and why it is there, then quote the most relevant part of the page you are linking to in case the target page is unavailable. [Answers that are little more than a link may be deleted.](/help/deleted-answers) – 4b0 Jun 30 '21 at 06:10