:relfileprefix: ../../../
[#boost-urls-params_base-count]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/params_base.adoc[pass:[params_base]]::count


Return the number of matching keys


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/params_base.hpp#L296[boost/url/params_base.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:std.adoc[std]::size_t
count(
    core::string_view key,
    xref:boost/urls/ignore_case_param.adoc[ignore_case_param] ic = = {}) const noexcept;
----

== Description


This function examines the
parameters in the container to
find the number of matches for
the specified key.
The comparison is performed as if all
escaped characters were decoded first.

=== Example
[,cpp]
----
assert( url_view( "?first=John&last=Doe" ).params().count( "first" ) == 1 );
----

=== Complexity

Linear in `this-&gt;buffer().size()`.

=== Exception Safety

Throws nothing.





== Parameters

|===
| Name | Description 

| *key*
| 
The key to match.
By default, a case-sensitive
comparison is used.

| *ic*
| 
An optional parameter. If
the value
xref:boost/urls/ignore_case.adoc[ignore_case]
is passed
here, the comparison is
case-insensitive.

|===