Sstrutt: Initial creation - content from Variables page

2013-06-21T14:39:56Z

Initial creation - content from Variables page

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Basic manipulation tasks can be carried out by using the string object's methods, eg <code> "string".PadRight(10) </code>, see <code> Get-Member -InputObject "Text" </code> for full details.

== Escape Characters ==
{|class="vwikitable"
|-
! Text !! Description
|-
| <code> `0 </code> || Null (also $null)
|-
| <code> `a </code> || Bell/system beep
|-
| <code> `b </code> || Backspace
|-
| <code> `f </code> || Form feed
|-
| <code> `n </code> || New line
|-
| <code> `r </code> || Carriage return
|-
| <code> `t </code> || Tab (horizontal)
|-
| <code> `v </code> || Vertical tab
|-
| <code> `' </code> || '
|-
| <code> `" </code> || "
|}

== Concatenation + ==
Strings can be concatenated together using the <code>+</code> operator, however its also possible to use interpolation within string, the following produce identical results...
<source lang="powershell">
$strAB = $strA + $strB # Concatenation
$strAB = "$strA $strB" # Interpolation
</source>

== Interpolation ==
Interpolation allows variables to be embedded into a string and to be resolved into their actual values. This works between double quotes, but not between single quotes...
<source lang="powershell">
PS E:\> $sub = "replaced"
PS E:\> Write-Output "Variable has been $sub"
Variable has been replaced
PS E:\> Write-Output 'Variable has been $sub'
Variable has been $sub
</source>

Note that you can't use interpolation when using string properties of an object....
<source lang="powershell">
$strAB = $strA.text + $strB.text # Works
$strAB = "$strA.text $strB.text" # Fails
</source>

== Search ==
To search for specific text in a string...
<source lang="powershell">
if (Select-String -InputObject $text -Pattern "StringToFind" -Quiet)
{
# StringToFind found in $text
}
</source>

== Match (basic) ==
To do a basic search/match...
<source lang="powershell">
if ($res.Contains("Success")) {
# String did contain
} else {
# Didn't
}
</source>
...which is much preferable to...
<source lang="powershell">
if ($res.CompareTo("Success")) {
# Didn't match (CompareTo returns 1 if comparison fails !)
} else {
# Did match
}
</source>

== Match (extract) ==
To extract text that matches a regex...
<source lang="powershell">
$res = [regex]::matches($line, "\d{4}-[A-Za-z]{3}-Week\d{1}.log")
if (-not $res.Count)
{
# No matches found
} else {
$res1 = $res.Item(1).Value # 1st match to regex
}
</source>
See [[Regular Expressions]] for further info on regex stuff.

== Replace ==
Basic find and replace can be done with a string's Replace method, eg to replace "\" with "\\" in the $query variable...
<source lang="powershell"> $query = $query.Replace("\", "\\") </source>
For proper regular expressions support, use the following syntax
<source lang="powershell"> $query = [regex]::Replace($query, "search", "replace") </source>

== Strip Whitespace ==
<source lang="powershell"> $string = $string.TrimEnd() </source>

[[category:PowerShell]]
[[category:Variables (PowerShell)]]

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Sstrutt: Initial creation - content from Variables page