In todays tutorial well learn to import Python lists into files. Well cover three main use cases:
- Import list into a new file [could be txt, csv, json or others].
- Append a list to an existing file.
- Write multiple lists to a file
- Write a list of dictionaries to a file
Save list to a new text / csv file
Well start by creating the new file using the file open method, then loop through the list and write the list elements each in a different line.
with open['my_file.csv', 'w'] as my_file: my_file.write['Office branches:' + '\n'] for branch in offices: my_file.write[branch + '\n'] print['File created']Append Python list to text / csv file
In this example, well first check whether our file exists in the operating system, and then append the list values to the file.
Heres the code to use:
from pathlib import Path my_file = Path['C:\Temp\my_file.xlsx'] # check if directory exists if my_file.is_file[]: with open [my_file, 'a'] as my_file: my_file.write['\n'+ 'Office branches:' + '\n'] for o in offices: my_file.write[o + '\n'] print['File updated'] else: print['File not available']Write multiple lists to a file with Python
We would like now to import multiple lists into the file. One list has offices and the second has the corresponding number of employees.
offices = ['Atlanta', 'Boston', 'New York', 'Miami'] employees = [100,120,140,150]Well now use the zip function to stitch the two lists, and then import them as needed into the a csv file.
Heres the output:
Export list of dictionaries to a file
Well use the json module to transfer the dictionary list.
dict1 = dict [Atlanta = 100, Boston = 120] dict2 = dict[NewYork = 140, Miami=150] my_dicts = [dict1, dict2] import json with open['my_dict.txt', 'w'] as my_file: json.dump[my_dicts, my_file]