How can I compare two arrays, removing similar items, without iterating through the whole array?

问题

Is it possible to compare two arrays and remove the values that are equal (if they are at the same index), without iterating through both arrays? Here is an example:

$array1 = @(1,2,3,4,5,6,7,23,44)
$array2 = @(1,1,3,4,5,7,6,23,45)

$array3 = $sudo_compare_function $array1 $array2

where $array3 would now contain an array of indexes where $array2 is different from $array1 array:

(1,5,6,8)

If there isn't something like this, is there an easy way to do something similar without iterating through both arrays?

回答1:

Use the Compare-Object cmdlet to get an array of differing values:

$array1 = @(1,2,3,4,5,6,7,23,44)
$array2 = @(1,1,3,4,5,7,6,23,45)

$array3 = @(Compare-Object $array1 $array2 | select -Expand InputObject

For comparing just the corresponding indexes you'll have to manually make the comparison:

function Compare-Indexes($a1, $a2) {
  $minindex = [math]::Min($a1.Length, $a2.Length)
  $maxindex = [math]::Max($a1.Length, $a2.Length)

  for ($i = 0; $i -le $minindex; $i++) {
    if ( $a1[$i] -ne $a2[$i] ) { $i }
  }
  for ( $i = $minindex + 1; $i -le $maxindex; $i++ ) { $i }
}

$array1 = @(1,2,3,4,5,6,7,23,44)
$array2 = @(1,1,3,4,5,7,6,23,45)

$array3 = Compare-Indexes $array1 $array2

来源：https://stackoverflow.com/questions/16657743/how-can-i-compare-two-arrays-removing-similar-items-without-iterating-through