#Create DataFrame
import pandas as pd
import numpy as np
from pandas import DataFrame, Series
df = DataFrame(
    {'integer':[1,2,3,6,7,23,8,3],
     'float':[2,3.4,5,6,2,4.7,4,8],
     'string':['saya',None,'aku','cinta','kamu','a','b','jika']}
)
df

#Change value by index
df.ix[6,'string']='a'
df.ix[7,'string']='a'
df

#Grouping data in DataFrame
grouped = df['float'].groupby(df['string'])
grouped.mean()

df2 = df.copy()
def operation_more_than_one_columns(x):
    return x*2, x*3

df2['star_by_2'], df2['star_by_3'] = zip(*df2['integer'].map(operation_more_than_one_columns))
df2

df3 = df.copy()
def sum_two_columns(series):
    return series['integer'] + series['float']

df3['sum_int_float'] = df3.apply(sum_two_columns,axis=1)
df3