apply function in pandas code example

Example 1: pandas apply function to column

df['a'] = df['a'].apply(lambda x: x + 1)

Example 2: pandas apply function to each row lambda

def EOQ(D,p,ck,ch):
    Q = math.sqrt((2*D*ck)/(ch*p))
    return Q
ch=0.2
ck=5
df['Q'] = df.apply(lambda row: EOQ(row['D'], row['p'], ck, ch), axis=1)
df

Example 3: give function to pandas apply

import pandas as pd


def sum(x, y, z, m):
    return (x + y + z) * m


df = pd.DataFrame({'A': [1, 2], 'B': [10, 20]})

df1 = df.apply(sum, args=(1, 2), m=10)
print(df1)

Example 4: pandas apply function to dataframe

# iterate using this syntax where df is the pandas.DataFrame
# N. B.: a single tuple is composed by the row index 
# and the values of the dataframe columns  

for row in df.itertuples():
  # do your stuff here