Question

To run a function on every value in a column of data in a Pandas dataframe. what pandas dataframe method do we use?

Answer 1

If you have any doubts please comment below. Please give upvote if you like this.

Answer:

Python's pandas library provides an member function in Dataframe class to apply a function along the axis of the Dataframe that is along each row or column.

pandas.apply(function , axis=0)

For more understanding example code is below.

Python Code:

# importing pandas
import pandas as pd

# Initialise the matrix with 3 columns val1,val2,val3
matrix = [(1,2,3),(4,5,6),(7,8,9),(10,11,12),(13,14,15),(16,17,18)]
df = pd.DataFrame(matrix, columns=["val1","val2","val3"])
# Print the taking dataframe
print("Contents of the dataframe in object df are ,")
print(df)

# Here lambda is the function to add 10 for every element in columns
modify = df.apply(lambda x:x+10,axis = 0)
# Printing the modified val1 column in dataframe
print("\nContents of the dataframe in object modify are,")
print(modify)