Python - Cast datatype of only a single column in a Pandas DataFrame

To cast only a single column, use the astype() method. Let us first create a DataFrame with 2 columns. One of them is a “float64” type and another “int64” −

dataFrame = pd.DataFrame( { "Reg_Price": [7000.5057, 1500, 5000, 8000, 9000.75768, 6000], "Units": [90, 120, 100, 150, 200, 130] } )

Check the types −

dataFrame.dtypes 

Let’s say we need to cast only a single column “Units” from int64 to int32. For that, use astype() −

dataFrame.astype({'Units': 'int32'}).dtypes

Example

Following is the code −

 import pandas as pd # Create DataFrame dataFrame = pd.DataFrame( { "Reg_Price": [7000.5057, 1500, 5000, 8000, 9000.75768, 6000], "Units": [90, 120, 100, 150, 200, 130] } ) print"DataFrame ...\n",dataFrame print"\nDataFrame Types ...\n",dataFrame.dtypes print"\nCast only a single column to int32..." print"\nUpdated DataFrame Types ...\n",dataFrame.astype({'Units': 'int32'}).dtypes 

Output

This will produce the following output −

DataFrame ... Reg_Price   Units 0 7000.50570     90 1 1500.00000    120 2 5000.00000    100 3 8000.00000    150 4 9000.75768    200 5 6000.00000    130 DataFrame Types ... Reg_Price   float64 Units         int64 dtype: object Cast only a single column to int32... Updated DataFrame Types ... Reg_Price   float64 Units         int32 dtype: object