objectif

Remplacer conditionnellement des valeurs.

code minimal

import pandas as pd
s = pd.Series([1,-1,2])
print(s.mask(s<0, 0).tolist())

utilisation

import pandas as pd
s = pd.Series([1,2,3])
print(s.where(s>1, other=0).tolist())

variante(s) utile(s)

import pandas as pd
df = pd.DataFrame({"x":[1,2,3]})
print(df.where(df>1).isna().sum().sum())

notes

• mask inverse la condition de where.