[#boost-urls-params_ref-set]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/params_ref.adoc[params_ref]::set
:relfileprefix: ../../../
:mrdocs:


Set a value

== Synopsis


Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/params_ref.hpp#L848[boost/url/params_ref.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/params_base/iterator.adoc[iterator]
xref:boost/urls/params_ref/set-09.adoc[set](
    xref:boost/urls/params_base/iterator.adoc[iterator] pos,
    core::string_view value);
----

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

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/params_base/iterator.adoc[iterator]
xref:boost/urls/params_ref/set-01.adoc[set](
    core::string_view key,
    core::string_view value,
    xref:boost/urls/ignore_case_param.adoc[ignore_case_param] ic = {});
----

[.small]#xref:boost/urls/params_ref/set-01.adoc[_» more..._]#

== Description


This function replaces the value of an        element at the specified position.

All iterators that are equal to        `pos` or come after are invalidated.


=== Example

[,cpp]
----
url u( "?id=42&id=69" );

u.params().set( u.params().begin(), "none" );

assert( u.encoded_query() == "id=none&id=69" );
----

=== Complexity

Linear in `this‐>url().encoded_query().size()`.


=== Exception Safety

Strong guarantee.        Calls to allocate may throw.



== Return Value


An iterator to the element.



== Parameters


|===
| Name | Description

| *pos*
| An iterator to the element.


| *value*
| The value to assign. The        empty string still counts as a value.        That is, `has_value` for the element        is true.


| *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.


|===



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