'Python: get a frequency count based on two columns (variables) in pandas dataframe some row appers

Hello I have the following dataframe.

    Group           Size

    Short          Small
    Short          Small
    Moderate       Medium
    Moderate       Small
    Tall           Large

I want to count the frequency of how many time the same row appears in the dataframe.

    Group           Size      Time

    Short          Small        2
    Moderate       Medium       1 
    Moderate       Small        1
    Tall           Large        1

Solution 1:^[1]

Update after pandas 1.1 value_counts now accept multiple columns

df.value_counts(["Group", "Size"])

You can also try pd.crosstab()

Group           Size

Short          Small
Short          Small
Moderate       Medium
Moderate       Small
Tall           Large

pd.crosstab(df.Group,df.Size)


Size      Large  Medium  Small
Group                         
Moderate      0       1      1
Short         0       0      2
Tall          1       0      0

EDIT: In order to get your out put

pd.crosstab(df.Group,df.Size).replace(0,np.nan).\
     stack().reset_index().rename(columns={0:'Time'})
Out[591]: 
      Group    Size  Time
0  Moderate  Medium   1.0
1  Moderate   Small   1.0
2     Short   Small   2.0
3      Tall   Large   1.0

Solution 2:^[2]

Other posibbility is using .pivot_table() and aggfunc='size'

df_solution = df.pivot_table(index=['Group','Size'], aggfunc='size')

Sources

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Solution	Source
Solution 1
Solution 2	asantz96

'Python: get a frequency count based on two columns (variables) in pandas dataframe some row appers

Solution 1:[1]

Solution 2:[2]

Sources

Related Questions

Solution 1:^[1]

Solution 2:^[2]