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<div class="section" id="pyspark-pandas-dataframe-melt">
<h1>pyspark.pandas.DataFrame.melt<a class="headerlink" href="#pyspark-pandas-dataframe-melt" title="Permalink to this headline"></a></h1>
<dl class="py method">
<dt id="pyspark.pandas.DataFrame.melt">
<code class="sig-prename descclassname">DataFrame.</code><code class="sig-name descname">melt</code><span class="sig-paren">(</span><em class="sig-param"><span class="n">id_vars</span><span class="p">:</span> <span class="n">Union[Any, Tuple[Any, …], List[Union[Any, Tuple[Any, …]]], None]</span> <span class="o">=</span> <span class="default_value">None</span></em>, <em class="sig-param"><span class="n">value_vars</span><span class="p">:</span> <span class="n">Union[Any, Tuple[Any, …], List[Union[Any, Tuple[Any, …]]], None]</span> <span class="o">=</span> <span class="default_value">None</span></em>, <em class="sig-param"><span class="n">var_name</span><span class="p">:</span> <span class="n">Union[str, List[str], None]</span> <span class="o">=</span> <span class="default_value">None</span></em>, <em class="sig-param"><span class="n">value_name</span><span class="p">:</span> <span class="n">str</span> <span class="o">=</span> <span class="default_value">'value'</span></em><span class="sig-paren">)</span> &#x2192; pyspark.pandas.frame.DataFrame<a class="reference internal" href="../../../_modules/pyspark/pandas/frame.html#DataFrame.melt"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#pyspark.pandas.DataFrame.melt" title="Permalink to this definition"></a></dt>
<dd><p>Unpivot a DataFrame from wide format to long format, optionally
leaving identifier variables set.</p>
<p>This function is useful to massage a DataFrame into a format where one
or more columns are identifier variables (<cite>id_vars</cite>), while all other
columns, considered measured variables (<cite>value_vars</cite>), are “unpivoted” to
the row axis, leaving just two non-identifier columns, ‘variable’ and
‘value’.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters</dt>
<dd class="field-odd"><dl class="simple">
<dt><strong>frame</strong><span class="classifier">DataFrame</span></dt><dd></dd>
<dt><strong>id_vars</strong><span class="classifier">tuple, list, or ndarray, optional</span></dt><dd><p>Column(s) to use as identifier variables.</p>
</dd>
<dt><strong>value_vars</strong><span class="classifier">tuple, list, or ndarray, optional</span></dt><dd><p>Column(s) to unpivot. If not specified, uses all columns that
are not set as <cite>id_vars</cite>.</p>
</dd>
<dt><strong>var_name</strong><span class="classifier">scalar, default ‘variable’</span></dt><dd><p>Name to use for the ‘variable’ column. If None it uses <cite>frame.columns.name</cite> or
‘variable’.</p>
</dd>
<dt><strong>value_name</strong><span class="classifier">scalar, default ‘value’</span></dt><dd><p>Name to use for the ‘value’ column.</p>
</dd>
</dl>
</dd>
<dt class="field-even">Returns</dt>
<dd class="field-even"><dl class="simple">
<dt>DataFrame</dt><dd><p>Unpivoted DataFrame.</p>
</dd>
</dl>
</dd>
</dl>
<p class="rubric">Examples</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">df</span> <span class="o">=</span> <span class="n">ps</span><span class="o">.</span><span class="n">DataFrame</span><span class="p">({</span><span class="s1">&#39;A&#39;</span><span class="p">:</span> <span class="p">{</span><span class="mi">0</span><span class="p">:</span> <span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="mi">1</span><span class="p">:</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="mi">2</span><span class="p">:</span> <span class="s1">&#39;c&#39;</span><span class="p">},</span>
<span class="gp">... </span> <span class="s1">&#39;B&#39;</span><span class="p">:</span> <span class="p">{</span><span class="mi">0</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">1</span><span class="p">:</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">2</span><span class="p">:</span> <span class="mi">5</span><span class="p">},</span>
<span class="gp">... </span> <span class="s1">&#39;C&#39;</span><span class="p">:</span> <span class="p">{</span><span class="mi">0</span><span class="p">:</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">1</span><span class="p">:</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">2</span><span class="p">:</span> <span class="mi">6</span><span class="p">}},</span>
<span class="gp">... </span> <span class="n">columns</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;A&#39;</span><span class="p">,</span> <span class="s1">&#39;B&#39;</span><span class="p">,</span> <span class="s1">&#39;C&#39;</span><span class="p">])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">df</span>
<span class="go"> A B C</span>
<span class="go">0 a 1 2</span>
<span class="go">1 b 3 4</span>
<span class="go">2 c 5 6</span>
</pre></div>
</div>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">ps</span><span class="o">.</span><span class="n">melt</span><span class="p">(</span><span class="n">df</span><span class="p">)</span>
<span class="go"> variable value</span>
<span class="go">0 A a</span>
<span class="go">1 B 1</span>
<span class="go">2 C 2</span>
<span class="go">3 A b</span>
<span class="go">4 B 3</span>
<span class="go">5 C 4</span>
<span class="go">6 A c</span>
<span class="go">7 B 5</span>
<span class="go">8 C 6</span>
</pre></div>
</div>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">df</span><span class="o">.</span><span class="n">melt</span><span class="p">(</span><span class="n">id_vars</span><span class="o">=</span><span class="s1">&#39;A&#39;</span><span class="p">)</span>
<span class="go"> A variable value</span>
<span class="go">0 a B 1</span>
<span class="go">1 a C 2</span>
<span class="go">2 b B 3</span>
<span class="go">3 b C 4</span>
<span class="go">4 c B 5</span>
<span class="go">5 c C 6</span>
</pre></div>
</div>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">df</span><span class="o">.</span><span class="n">melt</span><span class="p">(</span><span class="n">value_vars</span><span class="o">=</span><span class="s1">&#39;A&#39;</span><span class="p">)</span>
<span class="go"> variable value</span>
<span class="go">0 A a</span>
<span class="go">1 A b</span>
<span class="go">2 A c</span>
</pre></div>
</div>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">ps</span><span class="o">.</span><span class="n">melt</span><span class="p">(</span><span class="n">df</span><span class="p">,</span> <span class="n">id_vars</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;A&#39;</span><span class="p">,</span> <span class="s1">&#39;B&#39;</span><span class="p">])</span>
<span class="go"> A B variable value</span>
<span class="go">0 a 1 C 2</span>
<span class="go">1 b 3 C 4</span>
<span class="go">2 c 5 C 6</span>
</pre></div>
</div>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">df</span><span class="o">.</span><span class="n">melt</span><span class="p">(</span><span class="n">id_vars</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;A&#39;</span><span class="p">],</span> <span class="n">value_vars</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;C&#39;</span><span class="p">])</span>
<span class="go"> A variable value</span>
<span class="go">0 a C 2</span>
<span class="go">1 b C 4</span>
<span class="go">2 c C 6</span>
</pre></div>
</div>
<p>The names of ‘variable’ and ‘value’ columns can be customized:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">ps</span><span class="o">.</span><span class="n">melt</span><span class="p">(</span><span class="n">df</span><span class="p">,</span> <span class="n">id_vars</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;A&#39;</span><span class="p">],</span> <span class="n">value_vars</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;B&#39;</span><span class="p">],</span>
<span class="gp">... </span> <span class="n">var_name</span><span class="o">=</span><span class="s1">&#39;myVarname&#39;</span><span class="p">,</span> <span class="n">value_name</span><span class="o">=</span><span class="s1">&#39;myValname&#39;</span><span class="p">)</span>
<span class="go"> A myVarname myValname</span>
<span class="go">0 a B 1</span>
<span class="go">1 b B 3</span>
<span class="go">2 c B 5</span>
</pre></div>
</div>
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