<h3 dir="auto">Bug report</h3>
<p dir="auto"><strong>Bug summary</strong></p>

<p dir="auto">When using named arguments for x and y, the plots created with plt.plot respectively ax.plot are keeping empty. plt.errorbar (or ax.errorbar) are producing the desired output (see code below).<br>
The <a href="https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.plot.html#matplotlib.axes.Axes.plot" rel="nofollow">documentation</a> shows that x and y are valid named arguments.</p>
<p dir="auto"><strong>Code for reproduction</strong></p>

<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="import matplotlib.pyplot as plt
import numpy as np

x = np.arange(0, 12, .5)
y = np.random.rand(*x.shape)
plt.plot(x, y) #  works as expected
plt.plot(x=x, y=y) # shows empty plot
plt.errorbar(x=x, y=y) # works as expected"><pre class="notranslate"><span class="pl-k">import</span> <span class="pl-s1">matplotlib</span>.<span class="pl-s1">pyplot</span> <span class="pl-k">as</span> <span class="pl-s1">plt</span>
<span class="pl-k">import</span> <span class="pl-s1">numpy</span> <span class="pl-k">as</span> <span class="pl-s1">np</span>

<span class="pl-s1">x</span> <span class="pl-c1">=</span> <span class="pl-s1">np</span>.<span class="pl-en">arange</span>(<span class="pl-c1">0</span>, <span class="pl-c1">12</span>, <span class="pl-c1">.5</span>)
<span class="pl-s1">y</span> <span class="pl-c1">=</span> <span class="pl-s1">np</span>.<span class="pl-s1">random</span>.<span class="pl-en">rand</span>(<span class="pl-c1">*</span><span class="pl-s1">x</span>.<span class="pl-s1">shape</span>)
<span class="pl-s1">plt</span>.<span class="pl-en">plot</span>(<span class="pl-s1">x</span>, <span class="pl-s1">y</span>) <span class="pl-c">#  works as expected</span>
<span class="pl-s1">plt</span>.<span class="pl-en">plot</span>(<span class="pl-s1">x</span><span class="pl-c1">=</span><span class="pl-s1">x</span>, <span class="pl-s1">y</span><span class="pl-c1">=</span><span class="pl-s1">y</span>) <span class="pl-c"># shows empty plot</span>
<span class="pl-s1">plt</span>.<span class="pl-en">errorbar</span>(<span class="pl-s1">x</span><span class="pl-c1">=</span><span class="pl-s1">x</span>, <span class="pl-s1">y</span><span class="pl-c1">=</span><span class="pl-s1">y</span>) <span class="pl-c"># works as expected</span></pre></div>
<p dir="auto"><strong>Actual outcome</strong><br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/6933947/45471598-ddf68000-b731-11e8-92ed-b9d7591dd194.PNG"><img src="https://user-images.githubusercontent.com/6933947/45471598-ddf68000-b731-11e8-92ed-b9d7591dd194.PNG" alt="empty-diagram" style="max-width: 100%;"></a></p>

<p dir="auto"><strong>Expected outcome</strong><br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/6933947/45471603-e18a0700-b731-11e8-9855-8e5ebb56b925.PNG"><img src="https://user-images.githubusercontent.com/6933947/45471603-e18a0700-b731-11e8-9855-8e5ebb56b925.PNG" alt="desired-diagram" style="max-width: 100%;"></a><br>
or<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/6933947/45471642-041c2000-b732-11e8-8649-79b8c8c54482.PNG"><img src="https://user-images.githubusercontent.com/6933947/45471642-041c2000-b732-11e8-8649-79b8c8c54482.PNG" alt="desired-diagram2" style="max-width: 100%;"></a></p>


<p dir="auto"><strong>Matplotlib version</strong></p>

<ul dir="auto">
<li>Operating system: Windows 10x64</li>
<li>Matplotlib version: 2.2.3 (had the same issue with 2.2.2)</li>
<li>Matplotlib backend (<code class="notranslate">print(matplotlib.get_backend())</code>): 'module://ipykernel.pylab.backend_inline'</li>
<li>Python version: 3.6.2</li>
<li>Jupyter version (if applicable): 1.0.0  (Jupyter notebook 5.1.0rrc1)</li>
<li>Other libraries: numpy 1.14.5+mkl</li>
</ul>


<p dir="auto">Python was installed using WinPython, packages installed with pip.</p>
<p dir="auto">When I execute the following command:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="python3 -c &quot;import matplotlib.pyplot as plt; plt.plot(x=[0,1], y=[0,1]); plt.show()&quot;"><pre class="notranslate"><code class="notranslate">python3 -c "import matplotlib.pyplot as plt; plt.plot(x=[0,1], y=[0,1]); plt.show()"
</code></pre></div>
<p dir="auto">it outputs:</p>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/6614695/5990571/691ad1e6-a96b-11e4-9430-1b890e56b2b7.png"><img src="https://cloud.githubusercontent.com/assets/6614695/5990571/691ad1e6-a96b-11e4-9430-1b890e56b2b7.png" alt="Empty_Plot" style="max-width: 100%;"></a></p>
<hr>
<p dir="auto"><em>Edit</em>: I see my error.  I was not supposed to provide the data as keyword arguments. Indeed <code class="notranslate">plt.plot([0,1], [0,1])</code> works fine.</p>
<p dir="auto">I don't know anything about how matplotlib works, but perhaps <code class="notranslate">plot</code> should be able to handle this (similar to how <code class="notranslate">pandas.DataFrame.plot</code> can handle this):</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="import pandas as pd
df = pd.DataFrame([[0,0],[1,1]], columns=['A', 'B'])
df.plot('A', 'B')
df.plot(x='A', y='B')"><pre class="notranslate"><code class="notranslate">import pandas as pd
df = pd.DataFrame([[0,0],[1,1]], columns=['A', 'B'])
df.plot('A', 'B')
df.plot(x='A', y='B')
</code></pre></div>
<p dir="auto">If that's not desirable, then perhaps it could at least throw an error or give a warning that an unexpected keyword argument was given...</p>