热图可视化

Question

我有一个数据框 df1

df1.info() 


<class 'pandas.core.frame.DataFrame'>
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

看起来像这样：

 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

我尝试用 seaborn 创建一个热图来可视化两个日期之间的数据（例如这里在 '2015-08-01 23:10:00' 和 '2015-08-02 02:00:00 之间'）：我喜欢这样：

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'] >= date_debut) & (df1['TIMESTAMP'] < date_fin)]

sns.heatmap(df1.iloc[:,1:6:],annot=True, linewidths=.5)

我得到了附件中的热图

我现在的问题是如何将热图左侧的数字 (145...161) 替换为相应的时间戳值 (2015-08-01 05:10:00, 2015-08 -01 05:20:00, 2015-08-01 05:30:00, ...)

谢谢

最佳

我尝试进行修改：

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)

编辑

但我收到错误和警告：

C:\Users\Demonstrator\Anaconda3\lib\site-packages\ipykernel\__main__.py:2:
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
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:
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
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:
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
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)
<ipython-input-129-cec498d88cac> in <module>()
      9 
     10 #sns.heatmap(df1.iloc[:,1:6:],annot=True, linewidths=.5)
---> 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
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
C:\Users\Demonstrator\Anaconda3\lib\site-packages\seaborn\matrix.py in
init(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
C:\Users\Demonstrator\Anaconda3\lib\site-packages\seaborn\matrix.py in
_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()
C:\Users\Demonstrator\Anaconda3\lib\site-packages\numpy\core\_methods.py
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):
ValueError: zero-size array to reduction operation minimum which has no identity

@jeanrjc，看最后一张图，有个问题：图片太小了，右边有两条竖线（刻度）。我希望我现在清楚了

Answer 1

这是因为 TIMESTAMP 不是您的索引，来自 sns.heatmap 文档字符串：

yticklabels : list-like, int, or bool, optional If True, plot the row names of the dataframe. If False, don't plot the row names. If list-like, plot these alternate labels as the yticklabels. If an integer, use the index names but plot only every n label.

行名作为索引。

因此您可以相应地设置索引：

df1.set_index("TIMESTAMP", inplace=1)

并使用您的 sns 命令，它几乎可以正常工作。问题是你会有一个丑陋的日期表示。

或者，您可以这样做，而不是更改索引:

import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
...
...
ax = sns.heatmap(df1.iloc[:, 1:6:], annot=True, linewidths=.5)
ax.set_yticklabels([i.strftime("%Y-%m-%d %H:%M:%S") for i in df1.TIMESTAMP], rotation=0)

HTH

热图可视化

HeatMap visualization

python

heatmap

seaborn