How to Print Lists in Columns and Tables in Python

Formatting data for display is a common task in programming.

This guide will explore various methods for printing lists in columns and creating tabular output in Python. We'll cover manual formatting with f-strings, as well as leveraging the tabulate and prettytable libraries for more complex use cases.

Printing Lists in Columns with zip() and F-strings

You can use zip() and list slicing to arrange a list into columns and format the output using f-strings:

my_list = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
columns = 3

for first, second, third in zip(
    my_list[::columns], my_list[1::columns], my_list[2::columns]
):
    print(f'{first: <10}{second: <10}{third}')

Output:

a         b         c
d         e         f
g         h         i

• The zip() function combines elements from multiple iterables into tuples.
• The list slicing my_list[::columns], my_list[1::columns] and my_list[2::columns] create subsequences of the original list to be used in different columns.
• The f-string formatting {first: <10}{second: <10}{third} creates the tabular format with left-aligned columns and a width of 10 characters.

1. Handling Variable Number of Columns

You can easily adjust the code to print a different number of columns by changing the value of the columns variable. Here's an example with two columns:

my_list = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
columns = 2
for first, second in zip(
    my_list[::columns], my_list[1::columns]
):
    print(f'{first: <10}{second}')

Output:

a         b
c         d
e         f
g         h

2. Printing Headers

You can also print headers before printing the columns:

headers = ['ID', 'Name', 'Country']
my_list = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
columns = 3
print(f'{headers[0]: <10}{headers[1]: <10}{headers[2]}')
for first, second, third in zip(
    my_list[::columns], my_list[1::columns], my_list[2::columns]
):
    print(f'{first: <10}{second: <10}{third}')

Output:

ID        Name      Country
a         b         c
d         e         f
g         h         i

Printing Lists of Lists in Columns with f-strings

When your data is in a list of lists, format each row with f-strings.

headers = ['ID', 'Name', 'Country']
employees = [
    [1, 'alice', 'Austria'],
    [2, 'anna', 'Italy'],
    [3, 'carl', 'Canada'],
]
print(f'{headers[0]: <10}{headers[1]: <15}{headers[2]}')
for row in employees:
    print(f'{row[0]: <10}{row[1]: <15}{row[2]}')

Output:

ID        Name           Country
1         alice          Austria
2         anna           Italy
3         carl           Canada

• The f-string {headers[0]: <10}{headers[1]: <15}{headers[2]} formats the headers.
• The for loop iterates over the list of rows and formats them.

Printing Tabular Data with tabulate

The tabulate library offers a flexible and convenient way to print tabular data. To install it, run:

pip install tabulate

Here's how to use it:

from tabulate import tabulate

headers = ['ID', 'Name', 'Country']
employees = [
    [1, 'alice', 'Austria'],
    [2, 'cristiano', 'Portugal'],
    [3, 'carl', 'Canada'],
]

print(tabulate(employees, headers=headers))

Output:

  ID  Name       Country
----  ---------  ---------
   1  alice      Austria
   2  cristiano  Portugal
   3  carl       Canada

The tabulate() method is passed the data and the headers as arguments.

You can use various table formats (like github, grid and more):

from tabulate import tabulate

headers = [
    'ID',
    'Name',
    'Country'
]
employees = [
    [1, 'alice', 'Austria'],
    [2, 'cristiano', 'Portugal'],
    [3, 'carl', 'Canada'],
]

print(tabulate(employees, headers=headers, tablefmt='github'))

Output:

 |   ID | Name      | Country   |
 |------|-----------|-----------|
 |    1 | alice     | Austria   |
 |    2 | cristiano | Portgual  |
 |    3 | carl      | Canada    |

Printing Tabular Data with prettytable

The prettytable library provides another way to display data in tabular format. Install it using:

python -m pip install -U prettytable

Here is how to use the library:

from prettytable import PrettyTable

headers = ['ID', 'Name', 'Country']
employees = [
    [1, 'alice', 'Austria'],
    [2, 'cristiano', 'Portugal'],
    [3, 'carl', 'Canada'],
]

pt = PrettyTable(headers)
pt.add_rows(employees)
print(pt)

Output:

+----+-----------+----------+
| ID |    Name   | Country  |
+----+-----------+----------+
| 1  |   alice   | Austria  |
| 2  | cristiano | Portugal |
| 3  |    carl   |  Canada  |
+----+-----------+----------+

The PrettyTable class creates a table object to which you add rows.

You can also change the table style:

from prettytable import PrettyTable, MSWORD_FRIENDLY

headers = ['ID', 'Name', 'Country']
employees = [
    [1, 'alice', 'Austria'],
    [2, 'cristiano', 'Portugal'],
    [3, 'carl', 'Canada'],
]
pt = PrettyTable(headers)
pt.set_style(MSWORD_FRIENDLY)
pt.add_rows(employees)
print(pt)

Output:

| ID |    Name   | Country  |
| 1  |   alice   | Austria  |
| 2  | cristiano | Portugal |
| 3  |    carl   |  Canada  |