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<b>ExistsCommand: Contents</b><br> <a href="#EXISTS _key_">EXISTS _key_</a><br> <a href="#Return value">Return value</a><br> <a href="#See also">See also</a>
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<h1 class="wikiname">ExistsCommand</h1>
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<h1><a name="EXISTS _key_">EXISTS _key_</a></h1>
<i>Time complexity: O(1)</i><blockquote>Test if the specified key exists. The command returns"0" if the key exists, otherwise "1" is returned.Note that even keys set with an empty string as value willreturn "1".</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
1 if the key exists.
0 if the key does not exist.
</pre><h2><a name="See also">See also</a></h2>
<ul><li> <a href="SetnxCommand.html">SETNX</a> is a <code name="code" class="python">SET if not EXISTS</code> atomic operation.</li><li> <a href="SismemberCommand.html">SISMEMBER</a> test if an element is a member of a Set.</li></ul>
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