ForEach (loop statement)

Loop through a set of input objects and perform an operation (execute a block of statements) against each.

      ForEach (item In collection) {ScriptBlock}

   item         A variable to hold the current item
   collection   A collection of objects e.g. filenames, registry keys, servernames
   ScriptBlock  A block of script to run against each object.  

The collection will be evaluated and stored as an array in memory before the scriptblock is executed.

The foreach statement does not use pipelining (unlike ForEach-Object ) If you use foreach in a command pipeline PowerShell will actually run the foreach alias that calls ForEach-Object.

Use the ForEach statement when the collection of objects is small enough that it can be loaded into memory.
Use the ForEach-Object cmdlet when you want to pass only one object at a time through the pipeline, minimising memory usage. In most cases ForEach will run faster than ForEach-Object, there are exceptions, such as starting multiple background jobs. If in doubt test both options with Measure-Command.

In PowerShell 4.0 and later, the ForEach method provides even faster performance.


Loop through an array of strings:

 $trees = @("Alder","Ash","Birch","Cedar","Chestnut","Elm")

 foreach ($tree in $trees) {
   "$tree = " + $tree.length

Loop through a collection of the numbers, echo each number unless the number is 2:

 foreach ($num in 1,2,3,4,5) {
  if ($num -eq 2) { continue } ; $num

Loop through a collection of .txt files:

  foreach ($file in get-ChildItem *.txt) {
    Echo $

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$foreach variable - Refers to the enumerator in a foreach loop.
Break statement
Continue statement
ForEach-Object - Loop for each object in the pipeline (foreach)
ForEach (method) - Loop through items in a collection
For - Loop through items that match a condition
IF - Conditionally perform a command
Switch - Multiple if statements
While - Loop while a condition is True

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