<p dir="auto">Relevant <a href="https://stackoverflow.com/questions/23258353/seaborn-facetgrid-col-wrap-wide-to-long-plotting-issue/45377449#45377449" rel="nofollow">StackOverflow question</a> (which I actually just posted to).</p>
<p dir="auto">I understand this isn't a showstopper but actually made me research a while before realizing there was also a <code class="notranslate">row</code> parameter that was meant to be used. Perhaps a error message could be displayed?</p>
<p dir="auto">If you tell me what the intended behavior is I can try and make a pull request fixing it. <g-emoji class="g-emoji" alias="smile" fallback-src="https://github.githubassets.com/images/icons/emoji/unicode/1f604.png">😄</g-emoji></p>
<p dir="auto">I'm trying to plot side-by-side heatmaps and I'm seeing this problem when <code class="notranslate">sharey=True</code>. The ordering of the data in all but the last subplot is reversed. But because the y axis is shared, the overall figure displays incorrectly.</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
import pandas as pd
import seaborn as sns

df1 = pd.DataFrame(np.random.random((10,10,)))
df1.loc[2] = 0
df2 = pd.DataFrame(np.random.random((10,10,)))
df2.loc[7] = 0"><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-k">import</span> <span class="pl-s1">pandas</span> <span class="pl-k">as</span> <span class="pl-s1">pd</span>
<span class="pl-k">import</span> <span class="pl-s1">seaborn</span> <span class="pl-k">as</span> <span class="pl-s1">sns</span>

<span class="pl-s1">df1</span> <span class="pl-c1">=</span> <span class="pl-s1">pd</span>.<span class="pl-v">DataFrame</span>(<span class="pl-s1">np</span>.<span class="pl-s1">random</span>.<span class="pl-en">random</span>((<span class="pl-c1">10</span>,<span class="pl-c1">10</span>,)))
<span class="pl-s1">df1</span>.<span class="pl-s1">loc</span>[<span class="pl-c1">2</span>] <span class="pl-c1">=</span> <span class="pl-c1">0</span>
<span class="pl-s1">df2</span> <span class="pl-c1">=</span> <span class="pl-s1">pd</span>.<span class="pl-v">DataFrame</span>(<span class="pl-s1">np</span>.<span class="pl-s1">random</span>.<span class="pl-en">random</span>((<span class="pl-c1">10</span>,<span class="pl-c1">10</span>,)))
<span class="pl-s1">df2</span>.<span class="pl-s1">loc</span>[<span class="pl-c1">7</span>] <span class="pl-c1">=</span> <span class="pl-c1">0</span></pre></div>
<p dir="auto">Without <code class="notranslate">sharey=True</code></p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="fig, ax = plt.subplots(1,2)
sns.heatmap(df1, ax=ax[0])
sns.heatmap(df2, ax=ax[1]);"><pre class="notranslate"><span class="pl-s1">fig</span>, <span class="pl-s1">ax</span> <span class="pl-c1">=</span> <span class="pl-s1">plt</span>.<span class="pl-en">subplots</span>(<span class="pl-c1">1</span>,<span class="pl-c1">2</span>)
<span class="pl-s1">sns</span>.<span class="pl-en">heatmap</span>(<span class="pl-s1">df1</span>, <span class="pl-s1">ax</span><span class="pl-c1">=</span><span class="pl-s1">ax</span>[<span class="pl-c1">0</span>])
<span class="pl-s1">sns</span>.<span class="pl-en">heatmap</span>(<span class="pl-s1">df2</span>, <span class="pl-s1">ax</span><span class="pl-c1">=</span><span class="pl-s1">ax</span>[<span class="pl-c1">1</span>]);</pre></div>
<p dir="auto">Correctly shows as<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/2991876/62012940-058be680-b152-11e9-8e20-839efedcd9b8.png"><img src="https://user-images.githubusercontent.com/2991876/62012940-058be680-b152-11e9-8e20-839efedcd9b8.png" alt="image" style="max-width: 100%;"></a></p>
<p dir="auto">With <code class="notranslate">sharey=True</code></p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="fig, ax = plt.subplots(1,2, sharey=True)
sns.heatmap(df1, ax=ax[0])
sns.heatmap(df2, ax=ax[1]);"><pre class="notranslate"><span class="pl-s1">fig</span>, <span class="pl-s1">ax</span> <span class="pl-c1">=</span> <span class="pl-s1">plt</span>.<span class="pl-en">subplots</span>(<span class="pl-c1">1</span>,<span class="pl-c1">2</span>, <span class="pl-s1">sharey</span><span class="pl-c1">=</span><span class="pl-c1">True</span>)
<span class="pl-s1">sns</span>.<span class="pl-en">heatmap</span>(<span class="pl-s1">df1</span>, <span class="pl-s1">ax</span><span class="pl-c1">=</span><span class="pl-s1">ax</span>[<span class="pl-c1">0</span>])
<span class="pl-s1">sns</span>.<span class="pl-en">heatmap</span>(<span class="pl-s1">df2</span>, <span class="pl-s1">ax</span><span class="pl-c1">=</span><span class="pl-s1">ax</span>[<span class="pl-c1">1</span>]);</pre></div>
<p dir="auto">shows as<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/2991876/62012996-ab3f5580-b152-11e9-81c1-4a00be683bff.png"><img src="https://user-images.githubusercontent.com/2991876/62012996-ab3f5580-b152-11e9-81c1-4a00be683bff.png" alt="image" style="max-width: 100%;"></a></p>
<p dir="auto">The y axis on the left is reversed (and correctly labeled). But the values on the right are not reversed and because the y is shared, it is incorrect.</p>
<p dir="auto">I can't tell if this related to <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="266835659" data-permission-text="Title is private" data-url="https://github.com/mwaskom/seaborn/issues/1306" data-hovercard-type="issue" data-hovercard-url="/mwaskom/seaborn/issues/1306/hovercard" href="https://github.com/mwaskom/seaborn/issues/1306">#1306</a></p>
<p dir="auto">I found this issue after looking at<br>
<a href="https://stackoverflow.com/questions/28356359/one-colorbar-for-seaborn-heatmaps-in-subplot" rel="nofollow">https://stackoverflow.com/questions/28356359/one-colorbar-for-seaborn-heatmaps-in-subplot</a></p>
<p dir="auto">Using the code from the accepted answer (from mwaskom),</p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="fig, axn = plt.subplots(2, 2, sharex=True, sharey=True)
cbar_ax = fig.add_axes([.91, .3, .03, .4])

for i, ax in enumerate(axn.flat):
    sns.heatmap(df1, ax=ax,
                cbar=i == 0,
                vmin=0, vmax=1,
                cbar_ax=None if i else cbar_ax)"><pre class="notranslate"><span class="pl-s1">fig</span>, <span class="pl-s1">axn</span> <span class="pl-c1">=</span> <span class="pl-s1">plt</span>.<span class="pl-en">subplots</span>(<span class="pl-c1">2</span>, <span class="pl-c1">2</span>, <span class="pl-s1">sharex</span><span class="pl-c1">=</span><span class="pl-c1">True</span>, <span class="pl-s1">sharey</span><span class="pl-c1">=</span><span class="pl-c1">True</span>)
<span class="pl-s1">cbar_ax</span> <span class="pl-c1">=</span> <span class="pl-s1">fig</span>.<span class="pl-en">add_axes</span>([<span class="pl-c1">.91</span>, <span class="pl-c1">.3</span>, <span class="pl-c1">.03</span>, <span class="pl-c1">.4</span>])

<span class="pl-k">for</span> <span class="pl-s1">i</span>, <span class="pl-s1">ax</span> <span class="pl-c1">in</span> <span class="pl-en">enumerate</span>(<span class="pl-s1">axn</span>.<span class="pl-s1">flat</span>):
    <span class="pl-s1">sns</span>.<span class="pl-en">heatmap</span>(<span class="pl-s1">df1</span>, <span class="pl-s1">ax</span><span class="pl-c1">=</span><span class="pl-s1">ax</span>,
                <span class="pl-s1">cbar</span><span class="pl-c1">=</span><span class="pl-s1">i</span> <span class="pl-c1">==</span> <span class="pl-c1">0</span>,
                <span class="pl-s1">vmin</span><span class="pl-c1">=</span><span class="pl-c1">0</span>, <span class="pl-s1">vmax</span><span class="pl-c1">=</span><span class="pl-c1">1</span>,
                <span class="pl-s1">cbar_ax</span><span class="pl-c1">=</span><span class="pl-c1">None</span> <span class="pl-k">if</span> <span class="pl-s1">i</span> <span class="pl-k">else</span> <span class="pl-s1">cbar_ax</span>)</pre></div>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/2991876/62013072-957e6000-b153-11e9-95d3-c2942ec7661e.png"><img src="https://user-images.githubusercontent.com/2991876/62013072-957e6000-b153-11e9-95d3-c2942ec7661e.png" alt="image" style="max-width: 100%;"></a></p>
<p dir="auto">I'm getting plots 1, 2, 3 are reversed and 4 is okay. But in the original stackoverflow answer, all plots are okay (identical), so perhaps this is a bug in a recent version of seaborn?</p>
<p dir="auto">I'm using seaborn 0.9.0, matplotlib 3.1.0, python 3.7.3 on Mac OS X 10.14.5.</p>