hincrbyex.html

---
title: hincrbyex
brief: Increment a value in a hash only if it exists
updated: 2014-07-31 10:28:00
layout: script
sha: 3cb0d65c399fda8a1d4eb93b2fe85311671bc969
return: The new value of the counter if found, otherwise nil
---

<strong>Keys: 1</strong>
<ol class="args">
  <li>A hash containing a field to be used as a counter.</li>
</ol>

<strong>Args: 2</strong>
<ol class="args">
  <li>The field within the hash to use as a counter.</li>
  <li>The amount to increment the counter by.</li>
</ol>

<h2>Example</h2>

<pre class="script-example">
> evalsha 3cb0d65c399fda8a1d4eb93b2fe85311671bc969 1 guests sally 1
(nil)
> hset guests sally 8
(integer) 1
> evalsha 3cb0d65c399fda8a1d4eb93b2fe85311671bc969 1 guests sally 1
(integer) 9
> evalsha 3cb0d65c399fda8a1d4eb93b2fe85311671bc969 1 guests sally 1
(integer) 10
</pre>

<h2>Source</h2>

<pre class="script-source">
if redis.call("HEXISTS", KEYS[1], ARGV[1]) == 1 then
  return redis.call("HINCRBY", KEYS[1], ARGV[1], ARGV[2])
else
  return nil
end
</pre>