Search code examples
pythonpandasdataframebinning

How to bin column of floats with pandas


This code was working until I upgrade my python 2.x to 3.x. I have a df consisting of 3 columns ipk1, ipk2, ipk3. ipk1, ipk2, ipk3 consisting of float numbers 0 - 4.0, I would like to bin them into string.

The data looks something like this:

    ipk1    ipk2    ipk3    ipk4    ipk5    jk
0   3.25    3.31    3.31    3.31    3.34    P
1   3.37    3.33    3.36    3.33    3.41    P
2   3.41    3.47    3.59    3.55    3.60    P
3   3.23    3.10    3.05    2.98    2.97    L
4   3.24    3.40    3.22    3.23    3.25    L

on python 2.x this code works but after I upgrade it into python 3 it isn't. Is there any other way to bin it into string ? I have tried using while it also not help anything.

train1.loc[train1['ipk1'] > 3.6, 'ipk1'] = 'A',
train1.loc[(train1['ipk1']>3.2) & (train1['ipk1']<=3.6),'ipk1']='B',
train1.loc[(train1['ipk1']>2.8) & (train1['ipk1']<=3.2),'ipk1']='C',
train1.loc[(train1['ipk1']>2.4) & (train1['ipk1']<=2.8),'ipk1']='D',
train1.loc[(train1['ipk1']>2.0) & (train1['ipk1']<=2.4),'ipk1']='E',
train1.loc[(train1['ipk1']>1.6) & (train1['ipk1']<=2.0),'ipk1']='F',
train1.loc[(train1['ipk1']>1.2) & (train1['ipk1']<=1.6),'ipk1']='G',
train1.loc[train1['ipk1'] <= 1.2, 'ipk1'] = 'H' 

The error I receive:

TypeError: '>' not supported between instances of 'str' and 'float'

My expected output:

    ipk1    ipk2    ipk3    ipk4    ipk5    jk
0   B       3.31    3.31    3.31    3.34    P
1   B       3.33    3.36    3.33    3.41    P
2   B       3.47    3.59    3.55    3.60    P
3   B       3.10    3.05    2.98    2.97    L
4   B       3.40    3.22    3.23    3.25    L

Solution

  • This is a good use case for pandas.cut:

    bins = [-np.inf, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2, 3.6, np.inf]
    labels = ['H', 'G', 'F', 'E', 'D', 'C', 'B', 'A']
    
    df['ipk1'] = pd.cut(df['ipk1'], bins=bins, labels=labels)