Pandas - Conditional Probability of a given specific b

Question

I have DataFrame with two columns of \"a\" and \"b\". How can I find the conditional probability of \"a\" given specific \"b\"?

df.groupby(\'a\').groupby(\         


        

Answer 1

You could try this function,

def conprob(pd1,pd2,transpose=1):
    if transpose==0:
        table=pd.crosstab(pd1,pd2)
    else:
        table=pd.crosstab(pd2,pd1)
    cnames=table.columns.values
    weights=1/table[cnames].sum()
    out=table*weights
    pc=table[cnames].sum()/table[cnames].sum().sum()
    table=table.transpose()
    cnames=table.columns.values
    p=table[cnames].sum()/table[cnames].sum().sum()
    out['p']=p
    return out

This return de conditional probability P( row |column )