Powershell for total beginners lesson 12 Loops

Let’s do some loop’s, while, for, do until.

The ForEach-Object we already discussed.

The While loop is pretty simple one:

While(<whats in here is true>)

{

repeat this code here

} 

Simple example

$i = 0
while($i -lt 5)
{
  #print the value of $i
  $i 
  #add 1 to $i equal to $i = $i + 1
  $i++
}

 

Another more productive example:

#Read a file into $content variable
$content = Get-Content "C:\Temp\myTextFile.txt"
#Let's check what type or variable we are getting
$content.GetType()
$i = 0

#while $i is less then $content.Length which is the number of objects in our array
while($i -lt $content.Length)
{
  #Print string object $i from $content array which represents a line from C:\Temp\myTextFile.txt
  $content[$i]
  $i++
}

 

The for loop, in the for loop we have the initialization, condition and repeat inside the brackets like this:

for(initialization;condition;repeat)

{

Repeat the code here

}

This code will do the same as our first while example:

for($i=0;$i -lt 5;$i++)
{
  $i
}

 

The Do Until first does then checks:

Do

{

Repeat the code here

}

Until(<UNTIL THIS IS TRUE>)

For example:

$i = 0
Do
{
  $i
  $i++
}
Until($i -eq 5)

 

This is a nice one:

0..4 | %{
  $_
}

We already discussed the:

foreach($item in $items)
{
  do something with $item
}

And the:

$items | ForEach-Object{
  Do something with $_ (which is the current object)
}

The same as:

$items | %{
  Do something with $_ (which is the current object)
}

 

Tagged: Do Until, For, ForEach, Get-Content, Loop, Loops, While