---
name: "Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap"
section: "3pm"
platform: "linux"
package: "perl-perl-critic"
version: "1.156-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap"
---

# Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap(3pm)

Don't use "map" in void contexts.

## NAME

Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidMap - Don't use "map" in void contexts.

## AFFILIATION

This Policy is part of the core Perl::Critic distribution.

## DESCRIPTION

`"map"` and `"grep"` are intended to be pure functions, not mutators. If you want to iterate with side-effects, then you should use a proper `"for"` or `"foreach"` loop.

```
    grep{ print frobulate($_) } @list;           #not ok
    print map{ frobulate($_) } @list;            #ok
    grep{ $_ = lc $_ } @list;                    #not ok
    for( @list ){ $_ = lc $_  };                 #ok
    map{ push @frobbed, frobulate($_) } @list;   #not ok
    @frobbed = map { frobulate($_) } @list;      #ok
```

## CONFIGURATION

This Policy is not configurable except for the standard options.

## AUTHOR

Jeffrey Ryan Thalhammer \<jeff@imaginative-software.com\>

## COPYRIGHT

Copyright (c) 2005-2011 Imaginative Software Systems.  All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.  The full text of this license can be found in the LICENSE file included with this module.