In PowerShell switch is not just a way to avoid multiple if statements, it
is also a looping construct. In many cases this is a useful feature. But it
also introduces some difficulties and potential traps when switch is used
in other loops.
When break and continue are used inside of switch they work for this
switch. This is especially easy to forget for continue because in other
programming languages continue is not related to switch. The script
continue-works-for-switch.ps1 shows a typical mistake.
When switch is used in a script block with ForEach-Object or . {process{ ... }} there is another issue. The switch loop introduces its own automatic
variable $_ for the current object. This variable hides the automatic
variable $_ of the current pipeline object. The script
switch-hides-current-item.ps1 shows a typical mistake.
Yet another trap is use of break in order to skip next switch cases. This is
tempting because exactly break is used with switch in other languages. It
even works fine when switch is used on a single value. But when switch is
used on a collection, i.e. as a loop, then continue should be used for
skipping next cases. break stops the whole loop. The script
use-continue-not-break.ps1 shows some examples.
- Stack Overflow How to use break in switch -regex -file?