How to add a new category into the column of a dataframe in python?-CodePudding

I want to add a new category into my existing column based on some conditions like: child category is female age- male age

import pandas as pd
d = {'gender': ['male', 'female'], 'age': [3, 4]}
df = pd.DataFrame(data=d)

print(df)
gender  age
 male    3
female   4

output required:

gender  age
male     3
female   4
child    1

CodePudding user response：

you can add a row using DataFrame.append()

like this

import pandas as pd
d = {'gender': ['male', 'female'], 'age': [3, 4]}
df = pd.DataFrame(data=d)

df

gender	age
0	male
1	female

d2 = {'gender': ['child'], 'age': [1]}
d2 = pd.DataFrame(data=d2)
df = df.append(d2)
df

gender	age
0	male
1	female
2	child

CodePudding user response：

I don't understand the logic behind this but you can use append:

age = df.loc[df['gender'] == 'female', 'age'].squeeze() \
      - df.loc[df['gender'] == 'male', 'age'].squeeze()

df = df.append({'gender': 'child', 'age': age}, ignore_index=True)

Output:

>>> df
   gender  age
0    male    3
1  female    4
2   child    1