---
name: "Array::Diff"
section: "3pm"
platform: "linux"
package: "libarray-diff-perl"
version: "0.09-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Array::Diff"
---

# Array::Diff(3pm)

Find the differences between two arrays

## NAME

Array::Diff - Find the differences between two arrays

## SYNOPSIS

```
    my @old = ( 'a', 'b', 'c' );
    my @new = ( 'b', 'c', 'd' );
    my $diff = Array::Diff->diff( \@old, \@new );
    $diff->count   # 2
    $diff->added   # [ 'd' ];
    $diff->deleted # [ 'a' ];
```

## DESCRIPTION

This module compares two **pre-sorted** arrays and returns the added or deleted elements in two separate arrays. It's a simple wrapper around Algorithm::Diff.

**Note**: the arrays must be sorted before you call `"diff"`.

And if you need more complex array tools, check Array::Compare.

## METHODS

- new ()

  Create a new `"Array::Diff"` object.

- diff ( OLD, NEW )

  Compute the differences between two arrays.  The results are stored in the `"added"`, `"deleted"`, and `"count"` properties that may be examined using the corresponding methods.

  This method may be invoked as an object method, in which case it will recalculate the differences and repopulate the `"count"`, `"added"`, and `"removed"` properties, or as a static method, in which case it will return a newly-created `"Array::Diff"` object with the properties set appropriately.

- added ( \[VALUES \] )

  Get or set the elements present in the `"NEW"` array and absent in the `"OLD"` one at the comparison performed by the last `"diff()"` invocation.

- deleted ( \[VALUES\] )

  Get or set the elements present in the `"OLD"` array and absent in the `"NEW"` one at the comparison performed by the last `"diff()"` invocation.

- count ( \[VALUE\] )

  Get or set the total number of added or deleted elements at the comparison performed by the last `"diff()"` invocation. This count should be equal to the sum of the number of elements in the `"added"` and `"deleted"` properties.

## SEE ALSO

Array::Compare - performs the same function as this module, but has options for controlling how it works.

List::Compare - similar functionality, but again with more options.

Algorithm::Diff - the underlying implementation of the diff algorithm. If you've got Algorithm::Diff::XS installed, that will be used.

YAML::Diff - find difference between two YAML documents.

HTML::Differences - find difference between two HTML documents. This uses a more sane approach than HTML::Diff.

XML::Diff - find difference between two XML documents.

Hash::Diff - find the differences between two Perl hashes.

Data::Diff - find difference between two arbitrary data structures.

Text::Diff - can find difference between two inputs, which can be data structures or file names.

## AUTHOR

Daisuke Murase \<typester@cpan.org\>

## COPYRIGHT AND LICENSE

Copyright (c) 2009 by Daisuke Murase.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.