lambda code to capitalize column not working

Question

When I execute the Python 3.4.4 code below to capitalize values under the ident column, I get no errors but my output is not capitalized. Need help figuring out the problem.

import pandas as pd
import numpy as np
#Create a dataframe

data = {'ident': ['Jack', 'Mary', 'Teresa', 'James', 'Anna'], 
        'year': [2001, 2002, 2003, 2004, 2007], 
        'reports': [67, 5, 36, 9, 14],
        'scope': [17, 102, 57, 49, 77]
        }
df = pd.DataFrame(data, index = ['Bahia', 'Pico', 'Santa Fe', 'Maine', 
'Zuma'])
#Create a capitalizer function
capitalize = lambda x: x.upper()

#Create a capitalizing function over the column 'ident'

df['ident'].apply(capitalize)
print (df)

Answer 1

Changes to the data frame are not directly saved back. Replace

df['ident'].apply(capitalize)

with

df['ident'] = df['ident'].apply(capitalize)

and it will work.

So the complete code looks like:

import pandas as pd
import numpy as np
#Create a dataframe

data = {'ident': ['Jack', 'Mary', 'Teresa', 'James', 'Anna'],
        'year': [2001, 2002, 2003, 2004, 2007],
        'reports': [67, 5, 36, 9, 14],
        'scope': [17, 102, 57, 49, 77]
        }
df = pd.DataFrame(data, index = ['Bahia', 'Pico', 'Santa Fe', 'Maine','Zuma'])
#Create a capitalizer function
capitalize = lambda x: x.upper()

#Create a capitalizing function over the column 'ident'

df['ident'] = df['ident'].apply(capitalize)
print (df)

Or do it even nicer (imho) df.ident=df.ident.str.upper()