How to lowercase strings in a column in Pandas dataframe

Analyzing real-world data is somewhat difficult because we need to take various things into consideration. Apart from getting the useful data from large datasets, keeping data in required format is also very important. One might encounter a situation where we need to lowercase each letter in any specific column in given dataframe. Let’s see how to lowercase column names in Pandas dataframe. Let’s create a dataframe from the dict of lists. 

Python3

# Create a simple dataframe

# importing pandas as pd
import pandas as pd

# creating a dataframe
df = pd.DataFrame({'A': ['John', 'bODAY', 'MinA', 'Peter', 'nicky'],
                  'B': ['masters', 'graduate', 'graduate',
                                   'Masters', 'Graduate'],
                  'C': [27, 23, 21, 23, 24]})

df

Output: There are certain methods we can change/modify the case of column in pandas dataframe. Let’s see how can we lowercase column names in Pandas dataframe using lower() method. Method #1: 

Python3

# Create a simple dataframe

# importing pandas as pd
import pandas as pd


# creating a dataframe
df = pd.DataFrame({'A': ['John', 'bODAY', 'MinA', 'Peter', 'nicky'],
                  'B': ['masters', 'graduate', 'graduate',
                                   'Masters', 'Graduate'],
                  'C': [27, 23, 21, 23, 24]})

df['A'] = df['A'].str.lower()

df

Output: Method #2: 

Python3

# Create a simple dataframe

# importing pandas as pd
import pandas as pd


# creating a dataframe
df = pd.DataFrame({'A': ['John', 'bODAY', 'MinA', 'Peter', 'nicky'],
                  'B': ['masters', 'graduate', 'graduate',
                                   'Masters', 'Graduate'],
                  'C': [27, 23, 21, 23, 24]})

df['A'].apply(lambda x: x.lower())

Output: