[#bsl-unordered_map-02b-operator_subs-0de]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_map-02b.adoc[unordered&lowbar;map]::operator&lsqb;&rsqb;
:relfileprefix: ../../
:mrdocs:

Return a modifiable reference to the mapped value for `key`&period;

== Synopsis

Declared in `&lt;bslstl&lowbar;unorderedmap&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
add&lowbar;lvalue&lowbar;reference&lt;VALUE&gt;::type
operator&lsqb;&rsqb;(xref:bsl/unordered_map-02b/key_type.adoc[key&lowbar;type] const& key);
----

== Description

Return a reference providing modifiable access to the mapped&hyphen;value associated with the specified `key` in this unordered map&semi; if this unordered map does not already contain a `value&lowbar;type` object with `key`, first insert a new `value&lowbar;type` object having `key` and a default&hyphen;constructed `VALUE` object&period; Note that this method requires that the (template parameter) type `KEY` is `copy&hyphen;constructible` and the (template parameter) `VALUE` is &quot;default&hyphen;constructible&quot; (see &lcub;Requirements on `value&lowbar;type`&rcub;)&period;

== Return Value

modifiable reference to the mapped value

== Parameters

[cols="1,4"]
|===
| Name| Description
| *key*
| key to look up
|===


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