HeatMap visualization
<p>I have a dataframe  df1</p>

<pre><code>df1.info() 


&lt;class 'pandas.core.frame.DataFrame'&gt;
RangeIndex: 38840 entries, 0 to 38839
Data columns (total 7 columns):
TIMESTAMP                 38840 non-null datetime64[ns]
ACT_TIME_AERATEUR_1_F1    38696 non-null float64
ACT_TIME_AERATEUR_1_F3    38697 non-null float64
ACT_TIME_AERATEUR_1_F5    38695 non-null float64
ACT_TIME_AERATEUR_1_F6    38695 non-null float64
ACT_TIME_AERATEUR_1_F7    38693 non-null float64
ACT_TIME_AERATEUR_1_F8    38696 non-null float64
dtypes: datetime64[ns](1), float64(6)
memory usage: 2.1 MB
</code></pre>

<p>which looks like this : </p>

<pre><code> TIMESTAMP ACT_TIME_AERATEUR_1_F1 ACT_TIME_AERATEUR_1_F3 ACT_TIME_AERATEUR_1_F5 ACT_TIME_AERATEUR_1_F6 ACT_TIME_AERATEUR_1_F7
 ACT_TIME_AERATEUR_1_F8
 2015-08-01 05:10:00 100 100 100 100 100 100
 2015-08-01 05:20:00 100 100 100 100 100 100
 2015-08-01 05:30:00 100 100 100 100 100 100
 2015-08-01 05:40:00 100 100 100 100 100 100
</code></pre>

<p>I try to create a heatmap with seaborn to visualize data which are between two date ( for example here between '2015-08-01 23:10:00' and '2015-08-02 02:00:00') : 
I do like this : </p>

<pre><code>df1['TIMESTAMP']= pd.to_datetime(df_no_missing['TIMESTAMP'], '%d-%m-%y %H:%M:%S')
df1['date'] = df_no_missing['TIMESTAMP'].dt.date
df1['time'] = df_no_missing['TIMESTAMP'].dt.time
date_debut = pd.to_datetime('2015-08-01 23:10:00')
date_fin = pd.to_datetime('2015-08-02 02:00:00')

df1 = df1[(df1['TIMESTAMP'] &gt;= date_debut) &amp; (df1['TIMESTAMP'] &lt; date_fin)]

sns.heatmap(df1.iloc[:,1:6:],annot=True, linewidths=.5)
</code></pre>

<p>I got a heatmap like in the attached </p>

<p><img src="https://i.stack.imgur.com/KnWie.png" alt="enter image description here"></p>

<p>My question now is how can I replace the number in the left of the heatmap map (145...161) by their corresponding values of timestamp (2015-08-01 05:10:00, 2015-08-01 05:20:00, 2015-08-01 05:30:00, ...)</p>

<p>Thank you</p>

<p>Bests</p>

<p>I try to make modifications : </p>

<pre><code>df1.set_index("TIMESTAMP", inplace=1)
sns.heatmap(df1.iloc[:, 1:6:], annot=True, linewidths=.5)
ax = plt.gca()
ax.set_yticklabels([i.strftime("%Y-%m-%d %H:%M:%S") for i in df1.TIMESTAMP], rotation=0)
</code></pre>

<p><strong>EDIT</strong> </p>

<p>But I get error and warning : </p>

<blockquote>
<pre><code>C:\Users\Demonstrator\Anaconda3\lib\site-packages\ipykernel\__main__.py:2:
</code></pre>
  
  <p>SettingWithCopyWarning: 
      A value is trying to be set on a copy of a slice from a DataFrame.
      Try using .loc[row_indexer,col_indexer] = value instead</p>

<pre><code>See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
  from ipykernel import kernelapp as app
C:\Users\Demonstrator\Anaconda3\lib\site-packages\ipykernel\__main__.py:3:
</code></pre>
  
  <p>SettingWithCopyWarning: 
      A value is trying to be set on a copy of a slice from a DataFrame.
      Try using .loc[row_indexer,col_indexer] = value instead</p>

<pre><code>See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
  app.launch_new_instance()
C:\Users\Demonstrator\Anaconda3\lib\site-packages\ipykernel\__main__.py:4:
</code></pre>
  
  <p>SettingWithCopyWarning: 
      A value is trying to be set on a copy of a slice from a DataFrame.
      Try using .loc[row_indexer,col_indexer] = value instead</p>

<pre><code>See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy




---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
&lt;ipython-input-129-cec498d88cac&gt; in &lt;module&gt;()
      9 
     10 #sns.heatmap(df1.iloc[:,1:6:],annot=True, linewidths=.5)
---&gt; 11 sns.heatmap(df1.iloc[:, 1:6:], annot=True, linewidths=.5)
     12 ax = plt.gca()
     13 ax.set_yticklabels([i.strftime("%Y-%m-%d %H:%M:%S") for i in df1.TIMESTAMP], rotation=0)

C:\Users\Demonstrator\Anaconda3\lib\site-packages\seaborn\matrix.py in
</code></pre>
  
  <p>heatmap(data, vmin, vmax, cmap, center, robust, annot, fmt, annot_kws,
  linewidths, linecolor, cbar, cbar_kws, cbar_ax, square, ax,
  xticklabels, yticklabels, mask, **kwargs)
          483     plotter = _HeatMapper(data, vmin, vmax, cmap, center, robust, annot, fmt,
          484                           annot_kws, cbar, cbar_kws, xticklabels,
      --> 485                           yticklabels, mask)
          486 
          487     # Add the pcolormesh kwargs here</p>

<pre><code>C:\Users\Demonstrator\Anaconda3\lib\site-packages\seaborn\matrix.py in
</code></pre>
  
  <p><strong>init</strong>(self, data, vmin, vmax, cmap, center, robust, annot, fmt, annot_kws, cbar, cbar_kws, xticklabels, yticklabels, mask)
          165         # Determine good default values for the colormapping
          166         self._determine_cmap_params(plot_data, vmin, vmax,
      --> 167                                     cmap, center, robust)
          168 
          169         # Sort out the annotations</p>

<pre><code>C:\Users\Demonstrator\Anaconda3\lib\site-packages\seaborn\matrix.py in
</code></pre>
  
  <p>_determine_cmap_params(self, plot_data, vmin, vmax, cmap, center, robust)
          204         calc_data = plot_data.data[~np.isnan(plot_data.data)]
          205         if vmin is None:
      --> 206             vmin = np.percentile(calc_data, 2) if robust else calc_data.min()
          207         if vmax is None:
          208             vmax = np.percentile(calc_data, 98) if robust else calc_data.max()</p>

<pre><code>C:\Users\Demonstrator\Anaconda3\lib\site-packages\numpy\core\_methods.py
</code></pre>
  
  <p>in _amin(a, axis, out, keepdims)
           27 
           28 def _amin(a, axis=None, out=None, keepdims=False):
      ---> 29     return umr_minimum(a, axis, None, out, keepdims)
           30 
           31 def _sum(a, axis=None, dtype=None, out=None, keepdims=False):</p>

<pre><code>ValueError: zero-size array to reduction operation minimum which has no identity
</code></pre>
</blockquote>

<p>@jeanrjc, look at the last image, there is a problem: the image is too small and there is two vertical line(scale)on the right. I hope that i'am clear now<a href="https://i.stack.imgur.com/yNrA8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yNrA8.png" alt="enter image description here"></a></p>