[#boost-urls-params_base-find]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/params_base.adoc[params&lowbar;base]::find
:relfileprefix: ../../../
:mrdocs:


Find a matching key

== Synopsis


Declared in `&lt;https://www.github.com/boostorg/url/blob/develop/include/boost/url/params_base.hpp#L344[boost&sol;url&sol;params&lowbar;base&period;hpp]&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/params_base/iterator.adoc[iterator]
xref:boost/urls/params_base/find-09.adoc[find](
    core::string&lowbar;view key,
    xref:boost/urls/ignore_case_param.adoc[ignore&lowbar;case&lowbar;param] ic = &lcub;&rcub;) const noexcept;
----

[.small]#xref:boost/urls/params_base/find-09.adoc[_» more..._]#

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/params_base/iterator.adoc[iterator]
xref:boost/urls/params_base/find-04.adoc[find](
    xref:boost/urls/params_base/iterator.adoc[iterator] from,
    core::string&lowbar;view key,
    xref:boost/urls/ignore_case_param.adoc[ignore&lowbar;case&lowbar;param] ic = &lcub;&rcub;) const noexcept;
----

[.small]#xref:boost/urls/params_base/find-04.adoc[_» more..._]#

== Description


This function examines the parameters        in the container to find a match for        the specified key&period;        The comparison is performed as if all        escaped characters were decoded first&period;

The search starts from the first param        and proceeds forward until either the        key is found or the end of the range is        reached, in which case `end()` is        returned&period;


=== Example

[,cpp]
----
assert( (*url_view( "?first=John&last=Doe" ).params().find( "First", ignore_case )).value == "John" );
----

=== Effects

[,cpp]
----
return this->find( this->begin(), key, ic );
----

=== Complexity

Linear in `this&hyphen;&gt;buffer()&period;size()`&period;



== Return Value


an iterator to the param



== Parameters


|===
| Name | Description

| *key*
| The key to match&period;        By default, a case&hyphen;sensitive        comparison is used&period;


| *ic*
| An optional parameter&period; If        the value xref:boost/urls/ignore_case.adoc[ignore&lowbar;case] is passed        here, the comparison is        case&hyphen;insensitive&period;


| *from*
| The position to begin the            search from&period; This can be `end()`&period;


|===



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