CODEWITHSUNDEEP
powershellobjectmatchpipeline
FunnyO
FunnyO

Reputation: 403

How to select object with array-attribute match to variable?

I'm trying to select an Object-Output-Array from an Object-Array that has the Attribute Color to match with "blue", because the -match Operator has Performance Problems with matching the whole object-array to the Attribute (1-2 seconds on a large list)

Pseudocode:

$ObjectArray.Count => 999999 
$ObjectArray.Color = "Red"
$ObjectArray[2342] = "Blue"

<#
$result = $ObjectArray -match "Blue"  # Takes too Long

return $result
#>

# What I Need:
$result = Get-Object $Object from ObjectArray | where  
($ObjectArray.color -match "Blue")  # how to?

return $result

expected result:

$result
>> 
ID    : 2343
Color : Blue

$ObjectArray[0]
>>
ID    : 1
Color : Red

Upvotes: 3

Views: 2898

Answers (1)

AdminOfThings
AdminOfThings

Reputation: 25061

Assuming you only want the first match, this is what gave me the fastest search results:

$result = foreach ($obj in $objectarray) {
    if ($obj.color -eq "blue") {
        $obj
        break
    }
}

In my limited findings, -eq appears to be a faster operator than -match. Techniques that only return the first match can vary greatly depending on where the match exists within the array. A match at index 3 will return significantly quicker than a match at index 999999.

All tests below were done on an array with one million items.

Test Case 1: Using -match Against the Whole Object

Measure-Command {
 $result = $objectarray -match "blue"
 $result
 }


Days              : 0
Hours             : 0
Minutes           : 2
Seconds           : 3
Milliseconds      : 799
Ticks             : 1237994203
TotalDays         : 0.00143286366087963
TotalHours        : 0.0343887278611111
TotalMinutes      : 2.06332367166667
TotalSeconds      : 123.7994203
TotalMilliseconds : 123799.4203

Test Case 2: Using where() Method with Default Mode and Operator -eq

Measure-Command {
 $result = $objectarray.where{$_.color -eq "blue"}
 }


Days              : 0
Hours             : 0
Minutes           : 1
Seconds           : 8
Milliseconds      : 823
Ticks             : 688235093
TotalDays         : 0.000796568394675926
TotalHours        : 0.0191176414722222
TotalMinutes      : 1.14705848833333
TotalSeconds      : 68.8235093
TotalMilliseconds : 68823.5093

Test Case 3: Using Where() Method with First Mode

Measure-Command {
 $result = $objectarray.where({$_.color -eq "blue"},'First')
 }


Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 0
Milliseconds      : 12
Ticks             : 128258
TotalDays         : 1.48446759259259E-07
TotalHours        : 3.56272222222222E-06
TotalMinutes      : 0.000213763333333333
TotalSeconds      : 0.0128258
TotalMilliseconds : 12.8258

Test Case 4: Using foreach with break Statement

measure-command {
     $result = foreach ($obj in $objectarray) {
         if ($obj.color -eq "blue") {
             $obj
             break
         }
     }
 }


Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 0
Milliseconds      : 7
Ticks             : 74482
TotalDays         : 8.62060185185185E-08
TotalHours        : 2.06894444444444E-06
TotalMinutes      : 0.000124136666666667
TotalSeconds      : 0.0074482
TotalMilliseconds : 7.4482

Test Case 5: Using where() Method with -match operator

Measure-Command {
  $result = $objectarray.where{$_.color -match "^blue"}
  }


Days              : 0
Hours             : 0
Minutes           : 1
Seconds           : 25
Milliseconds      : 58
Ticks             : 850588447
TotalDays         : 0.000984477369212963
TotalHours        : 0.0236274568611111
TotalMinutes      : 1.41764741166667
TotalSeconds      : 85.0588447
TotalMilliseconds : 85058.8447

Test Case 6: Piping to Where-Object

Measure-Command {
  $result = $objectarray | where-object {$_.color -eq "blue"}
  }


Days              : 0
Hours             : 0
Minutes           : 2
Seconds           : 50
Milliseconds      : 478
Ticks             : 1704782030
TotalDays         : 0.00197312734953704
TotalHours        : 0.0473550563888889
TotalMinutes      : 2.84130338333333
TotalSeconds      : 170.478203
TotalMilliseconds : 170478.203

Upvotes: 2

Related Questions