CODEWITHSUNDEEP
pythonpandas
Fran Martinez
Fran Martinez

Reputation: 679

Pandas data frame with frequencies

I have a data frame that I plan building a histogram with.

The data frame contains the following values.

   starttime hour  
1  7/01/2015    0 
2  7/01/2015    0   
3  7/01/2015    3  
4  7/01/2015    3 
5  7/01/2015    12

I want to have the resulting data frame.

   starttime hour     frequency
1  7/01/2015    0             2
2  7/01/2015    3             2
3  7/01/2015    12            1

What I have done so far

df_values = Df[['starttime','hour']]
values = df_values.groupby(['starttime'])
grouped = values.aggregate(np.sum)

Output I'm getting

                                                        hour
starttime                                                   
6/01/2015  0000000000000000000000000000000000000000000000...
6/02/2015  0000000000000000000000000000000000000000000000...
6/03/2015  0000000000000000000000000000000000000000000000...
6/04/2015                                                NaN
6/05/2015                                             435211

Any help is greatly appreciated. Thanks.

Upvotes: 0

Views: 75

Answers (2)

Diego Aguado
Diego Aguado

Reputation: 1596

df['freq'] = 1 df.groupby(['starttime','hour', as_index=False]).count()

Upvotes: 0

cs95
cs95

Reputation: 402323

Use groupby + size/count -

c = df.columns.tolist() # c = ['starttime', 'hour']
df.groupby(c).size().reset_index(name='frequency')

Or,

df.groupby(c).hour.count().reset_index(name='frequency')


   starttime  hour  frequency
0  7/01/2015     0          2
1  7/01/2015     3          2
2  7/01/2015    12          1

Upvotes: 2

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