Pivoting a pandas dataframe to generate a (seaborn) heatmap

Brainlock Published at Dev

Brainlock

I'm new to Python and fairly new to SO.

I have a pandas dataframe named df which looks like:

                                 Text
Date        Location                           
2015-07-08  San Diego, CA        1
2015-07-07  Bellevue, WA         1
            Los Angeles, CA      1
            New York, NY         1
            Los Angeles, CA      1
            Unknown              1

I want to pivot the data using:

import pandas, numpy as np

df_pivoted = df.pivot_table(df, values=['Text'], index=['Date'],
    columns=['Location'],aggfunc=np.sum)

The idea is to generate a heat map that shows the count of "Text" by "Location" and "Date".

I get error:

TypeError: pivot_table() got multiple values for keyword argument 'values'

When using a simplified approach:

df = df.pivot_table('Date', 'Location', 'Text')

I get error:

raise DataError('No numeric types to aggregate')

I'm using Python 2.7 and Pandas 0.16.2

In[2]: df.dtypes
Out[2]: 
Date        datetime64[ns]
Text                object
Location            object
dtype: object

Anyone having an idea?

Jianxun Li

import pandas as pd
import numpy as np

# just try to replicate your dataframe
# ==============================================
date = ['2015-07-08', '2015-07-07', '2015-07-07', '2015-07-07', '2015-07-07', '2015-07-07']
location = ['San Diego, CA', 'Bellevue, WA', 'Los Angeles, CA', 'New York, NY', 'Los Angeles, CA', 'Unknown']
text = [1] * 6
df = pd.DataFrame({'Date': date, 'Location': location, 'Text': text})

Out[141]: 
         Date         Location  Text
0  2015-07-08    San Diego, CA     1
1  2015-07-07     Bellevue, WA     1
2  2015-07-07  Los Angeles, CA     1
3  2015-07-07     New York, NY     1
4  2015-07-07  Los Angeles, CA     1
5  2015-07-07          Unknown     1

# processing
# ==============================================
pd.pivot_table(df, index='Date', columns='Location', values='Text', aggfunc=np.sum)

Out[142]: 
Location    Bellevue, WA  Los Angeles, CA  New York, NY  San Diego, CA  Unknown
Date                                                                           
2015-07-07             1                2             1            NaN        1
2015-07-08           NaN              NaN           NaN              1      NaN

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