Python program to convert Dict of list to CSV

Given a dictionary of list d, the task is to write a Python program to write a dictionary into a CSV file.

The idea to solve this problem is to zip the dictionary and then write it into a CSV file. Python provides an in-built module called ‘csv’ for working with CSV files. csv.writer class is used to write into CSV file. csv.writer class provide two methods for writing into csv file.

• writerow(): writerow() method is used to write single row.
• writerows(): writerows() method is used to write multiple rows.

Python3

# Program to write a dictionary of list to csv
import csv

# dictionary of list
d = {"key1": ['a', 'b', 'c'],
     "key2": ['d', 'e', 'f'],
     "key3": ['g', 'h', 'i']}

# writing to csv file
with open("test.csv", "w") as outfile:

    # creating a csv writer object
    writerfile = csv.writer(outfile)

    # writing dictionary keys as headings of csv
    writerfile.writerow(d.keys())

    # writing list of dictionary
    writerfile.writerows(zip(*d.values()))

Output:

Python’s zip() function takes iterable as input and returns an iterator object. This iterator generates a series of tuples with each tuple having elements from each of the iterable. 

Here lists in the dictionary are provided as input to the zip() and it will return a series of tuples with each tuple having elements from all lists these tuples will be treated as rows for CSV file.

Example:

Python3

# Program to write a dictionary of list to csv
import csv

# dictionary of list
d = {"key1": ['a', 'b', 'c'],
     "key2": ['d', 'e', 'f'],
     "key3": ['g', 'h', 'i']}

# writing to csv file
with open("test.csv", "w") as outfile:

    # creating a csv writer object
    writerfile = csv.writer(outfile)

    # writing dictionary keys as headings of csv
    writerfile.writerow(d.keys())

    # writing list of dictionary
    writerfile.writerows(zip(*d.values()))

Output: