Comparison Operators

The following operators are all Case-Insensitive by default:

  • -eq Equal
  • -ne Not equal
  • -ge Greater than or equal
  • -gt Greater than
  • -lt Less than
  • -le Less than or equal
  • -like Wildcard comparison
  • -notlike Wildcard comparison
  • -match Regular expression comparison
  • -notmatch Regular expression comparison
  • -replace Replace operator
  • -contains Containment operator
  • -notcontains Containment operator
  • -in Like –contains, but with the operands reversed.(PowerShell 3.0)
  • -notin Like –notcontains, but with the operands reversed.(PowerShell 3.0)

To perform a Case-Sensitive comparison just prefix any of the above with "c" for example -ceq for case-sensitive Equals or -creplace for case-sensitive replace.

Similarly prefixing with "i" will explicitly make the operator explicitly case insensitive. It seems likely that these short names such as -eq were chosen for operators instead of symbols (= / <> etc) to allow for these case sensitive options.

Types

  • -is Is of a type
  • -isnot Is not of a type
  • -as As a type, no error if conversion fails

Logical operators

  • -and Logical And
  • -or Logical Or
  • -xor Logical exclusive Or
  • -not logical not
  • ! logical not

Bitwise operators

  • -band Bitwise and
  • -bor Bitwise or
  • -bXor Bitwise OR (exclusive)
  • -bNot Bitwise NOT
  • -shl Shift bits left (PowerShell 3.0)
  • -shr Shift bits right – preserves sign for signed values.(PowerShell 3.0)

Format Operator

"format_string" -f Object1, Object2,...

The format_string is in the form: {0,-5} {1,-20} {2,-10}

In each set of braces, the first number, before the comma refers to the column. The second number, after the comma determines the padding (how many characters) If the second number is negative, it not only pads the element, but aligns it vertically. Optionally the second number can be used for formatting :hh :mm :C :p

When applied to an array, comparison operators will work as a filter returning all the values which match.

Filters

A PowerShell Filter will accept the following operators

  • -eq
  • -ne
  • -ge
  • -gt
  • -lt
  • -le
  • -like
  • -notlike
  • -approx
  • -bor
  • -band
  • -recursivematch

Notice that this list misses out several useful operators such as -match and -contains but those can still be used by piping to a Where-Object clause: ... | Where {$_.name –match 'value'}

Examples

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$demo = $null
if (-Not ($demo)) { write "Zero, null or Empty"}
if (!($demo)) { write "Zero, null or Empty"}

$myVar -is "String"
$myVar -eq 123 
$myVar -ceq $myVar2 
"abcdef" -like "abc*"
"abcdef" -replace "dEf","xyz"
$myVar1 -is "String" -and $myVar2 -is "Int"
"{2:N}" -f 24.4567
(1 -eq 1) -and -not (2 -gt 2) 

$mycmd = ps | select id,ProcessName
foreach ($proc in $mycmd) {"{0,-8}{1,-20}" -f $proc.id, $proc.ProcessName}

Related PowerShell Cmdlets:

  • if - Conditionally perform a command.
  • Assignment Operators ( $variable = X, $variable += Y )
  • PowerShell Regular Expressions
  • Format-Table