I am quite new to Python and I am now struggling with formatting my data nicely for printed output.

I have one list that is used for two headings, and a matrix that should be the contents of the table. Like so:

teams_list = ["Man Utd", "Man City", "T Hotspur"]
data = np.array([[1, 2, 1],
                 [0, 1, 0],
                 [2, 4, 2]])

Note that the heading names are not necessarily the same lengths. The data entries are all integers, though.

Now, I want to represent this in a table format, something like this:

            Man Utd   Man City   T Hotspur
  Man Utd         1          0           0
 Man City         1          1           0
T Hotspur         0          1           2

I have a hunch that there must be a data structure for this, but I cannot find it. I have tried using a dictionary and formatting the printing, I have tried for-loops with indentation and I have tried printing as strings.

I am sure there must be a very simple way to do this, but I am probably missing it due to lack of experience.

Some ad-hoc code for Python 2.7:

row_format ="{:>15}" * (len(teams_list) + 1)
print(row_format.format("", *teams_list))
for team, row in zip(teams_list, data):
    print(row_format.format(team, *row))

This relies on str.format() and the Format Specification Mini-Language.

There are some light and useful python packages for this purpose:

1. tabulate: https://pypi.python.org/pypi/tabulate

from tabulate import tabulate
print(tabulate([['Alice', 24], ['Bob', 19]], headers=['Name', 'Age']))

Name      Age
------  -----
Alice      24
Bob        19

tabulate has many options to specify headers and table format.

print(tabulate([['Alice', 24], ['Bob', 19]], headers=['Name', 'Age'], tablefmt='orgtbl'))

| Name   |   Age |
|--------+-------|
| Alice  |    24 |
| Bob    |    19 |

2. PrettyTable: https://pypi.python.org/pypi/PrettyTable

from prettytable import PrettyTable
t = PrettyTable(['Name', 'Age'])
t.add_row(['Alice', 24])
t.add_row(['Bob', 19])
print(t)

+-------+-----+
|  Name | Age |
+-------+-----+
| Alice |  24 |
|  Bob  |  19 |
+-------+-----+

PrettyTable has options to read data from csv, html, sql database. Also you are able to select subset of data, sort table and change table styles.

3. texttable: https://pypi.python.org/pypi/texttable

from texttable import Texttable
t = Texttable()
t.add_rows([['Name', 'Age'], ['Alice', 24], ['Bob', 19]])
print(t.draw())

+-------+-----+
| Name  | Age |
+=======+=====+
| Alice | 24  |
+-------+-----+
| Bob   | 19  |
+-------+-----+

with texttable you can control horizontal/vertical align, border style and data types.

4. termtables: https://github.com/nschloe/termtables

import termtables as tt

string = tt.to_string(
    [["Alice", 24], ["Bob", 19]],
    header=["Name", "Age"],
    style=tt.styles.ascii_thin_double,
    # alignment="ll",
    # padding=(0, 1),
)
print(string)

+-------+-----+
| Name  | Age |
+=======+=====+
| Alice | 24  |
+-------+-----+
| Bob   | 19  |
+-------+-----+

with texttable you can control horizontal/vertical align, border style and data types.

Other options:

• terminaltables Easily draw tables in terminal/console applications from a list of lists of strings. Supports multi-line rows.
• asciitable Asciitable can read and write a wide range of ASCII table formats via built-in Extension Reader Classes.

>>> import pandas
>>> pandas.DataFrame(data, teams_list, teams_list)
           Man Utd  Man City  T Hotspur
Man Utd    1        2         1        
Man City   0        1         0        
T Hotspur  2        4         2        

Python actually makes this quite easy.

Something like

for i in range(10):
    print '%-12i%-12i' % (10 ** i, 20 ** i)

will have the output

1           1           
10          20          
100         400         
1000        8000        
10000       160000      
100000      3200000     
1000000     64000000    
10000000    1280000000  
100000000   25600000000
1000000000  512000000000

The % within the string is essentially an escape character and the characters following it tell python what kind of format the data should have. The % outside and after the string is telling python that you intend to use the previous string as the format string and that the following data should be put into the format specified.

In this case I used “%-12i” twice. To break down each part:

'-' (left align)
'12' (how much space to be given to this part of the output)
'i' (we are printing an integer)

From the docs: https://docs.python.org/2/library/stdtypes.html#string-formatting

Updating Sven Marnach’s answer to work in Python 3.4:

row_format ="{:>15}" * (len(teams_list) + 1)
print(row_format.format("", *teams_list))
for team, row in zip(teams_list, data):
    print(row_format.format(team, *row))

When I do this, I like to have some control over the details of how the table is formatted. In particular, I want header cells to have a different format than body cells, and the table column widths to only be as wide as each one needs to be. Here’s my solution:

def format_matrix(header, matrix,
                  top_format, left_format, cell_format, row_delim, col_delim):
    table = [[''] + header] + [[name] + row for name, row in zip(header, matrix)]
    table_format = [['{:^{}}'] + len(header) * [top_format]] \
                 + len(matrix) * [[left_format] + len(header) * [cell_format]]
    col_widths = [max(
                      len(format.format(cell, 0))
                      for format, cell in zip(col_format, col))
                  for col_format, col in zip(zip(*table_format), zip(*table))]
    return row_delim.join(
               col_delim.join(
                   format.format(cell, width)
                   for format, cell, width in zip(row_format, row, col_widths))
               for row_format, row in zip(table_format, table))

print format_matrix(['Man Utd', 'Man City', 'T Hotspur', 'Really Long Column'],
                    [[1, 2, 1, -1], [0, 1, 0, 5], [2, 4, 2, 2], [0, 1, 0, 6]],
                    '{:^{}}', '{:<{}}', '{:>{}.3f}', '\n', ' | ')

Here’s the output:

                   | Man Utd | Man City | T Hotspur | Really Long Column
Man Utd            |   1.000 |    2.000 |     1.000 |             -1.000
Man City           |   0.000 |    1.000 |     0.000 |              5.000
T Hotspur          |   2.000 |    4.000 |     2.000 |              2.000
Really Long Column |   0.000 |    1.000 |     0.000 |              6.000

I think this is what you are looking for.

It’s a simple module that just computes the maximum required width for the table entries and then just uses rjust and ljust to do a pretty print of the data.

If you want your left heading right aligned just change this call:

 print >> out, row[0].ljust(col_paddings[0] + 1),

From line 53 with:

 print >> out, row[0].rjust(col_paddings[0] + 1),

I know that I am late to the party, but I just made a library for this that I think could really help. It is extremely simple, that’s why I think you should use it. It is called TableIT.

Basic Use

To use it, first follow the download instructions on the GitHub Page.

Then import it:

import TableIt

Then make a list of lists where each inner list is a row:

table = [
    [4, 3, "Hi"],
    [2, 1, 808890312093],
    [5, "Hi", "Bye"]
]

Then all you have to do is print it:

TableIt.printTable(table)

This is the output you get:

+--------------------------------------------+
| 4            | 3            | Hi           |
| 2            | 1            | 808890312093 |
| 5            | Hi           | Bye          |
+--------------------------------------------+

Field Names

You can use field names if you want to (if you aren’t using field names you don’t have to say useFieldNames=False because it is set to that by default):

TableIt.printTable(table, useFieldNames=True)

From that you will get:

+--------------------------------------------+
| 4            | 3            | Hi           |
+--------------+--------------+--------------+
| 2            | 1            | 808890312093 |
| 5            | Hi           | Bye          |
+--------------------------------------------+

There are other uses to, for example you could do this:

import TableIt

myList = [
    ["Name", "Email"],
    ["Richard", "richard@fakeemail.com"],
    ["Tasha", "tash@fakeemail.com"]
]

TableIt.print(myList, useFieldNames=True)

From that:

+-----------------------------------------------+
| Name                  | Email                 |
+-----------------------+-----------------------+
| Richard               | richard@fakeemail.com |
| Tasha                 | tash@fakeemail.com    |
+-----------------------------------------------+

Or you could do:

import TableIt

myList = [
    ["", "a", "b"],
    ["x", "a + x", "a + b"],
    ["z", "a + z", "z + b"]
]

TableIt.printTable(myList, useFieldNames=True)

And from that you get:

+-----------------------+
|       | a     | b     |
+-------+-------+-------+
| x     | a + x | a + b |
| z     | a + z | z + b |
+-----------------------+

Colors

You can also use colors.

You use colors by using the color option (by default it is set to None) and specifying RGB values.

Using the example from above:

import TableIt

myList = [
    ["", "a", "b"],
    ["x", "a + x", "a + b"],
    ["z", "a + z", "z + b"]
]

TableIt.printTable(myList, useFieldNames=True, color=(26, 156, 171))

Then you will get:

Please note that printing colors might not work for you but it does works the exact same as the other libraries that print colored text. I have tested and every single color works. The blue is not messed up either as it would if using the default 34m ANSI escape sequence (if you don’t know what that is it doesn’t matter). Anyway, it all comes from the fact that every color is RGB value rather than a system default.

More Info

For more info check the GitHub Page

Pure Python 3

def print_table(data, cols, wide):
    '''Prints formatted data on columns of given width.'''
    n, r = divmod(len(data), cols)
    pat = '{{:{}}}'.format(wide)
    line = '\n'.join(pat * cols for _ in range(n))
    last_line = pat * r
    print(line.format(*data))
    print(last_line.format(*data[n*cols:]))

data = [str(i) for i in range(27)]
print_table(data, 6, 12)

Will print

0           1           2           3           4           5           
6           7           8           9           10          11          
12          13          14          15          16          17          
18          19          20          21          22          23          
24          25          26

A simple way to do this is to loop over all columns, measure their width, create a row_template for that max width, and then print the rows. It’s not exactly what you are looking for, because in this case, you first have to put your headings inside the table, but I’m thinking it might be useful to someone else.

table = [
    ["", "Man Utd", "Man City", "T Hotspur"],
    ["Man Utd", 1, 0, 0],
    ["Man City", 1, 1, 0],
    ["T Hotspur", 0, 1, 2],
]
def print_table(table):
    longest_cols = [
        (max([len(str(row[i])) for row in table]) + 3)
        for i in range(len(table[0]))
    ]
    row_format = "".join(["{:>" + str(longest_col) + "}" for longest_col in longest_cols])
    for row in table:
        print(row_format.format(*row))

You use it like this:

>>> print_table(table)

            Man Utd   Man City   T Hotspur
  Man Utd         1          0           0
 Man City         1          1           0
T Hotspur         0          1           2

The following function will create the requested table (with or without numpy) with Python 3 (maybe also Python 2). I have chosen to set the width of each column to match that of the longest team name. You could modify it if you wanted to use the length of the team name for each column, but will be more complicated.

Note: For a direct equivalent in Python 2 you could replace the zip with izip from itertools.

def print_results_table(data, teams_list):
    str_l = max(len(t) for t in teams_list)
    print(" ".join(['{:>{length}s}'.format(t, length = str_l) for t in [" "] + teams_list]))
    for t, row in zip(teams_list, data):
        print(" ".join(['{:>{length}s}'.format(str(x), length = str_l) for x in [t] + row]))

teams_list = ["Man Utd", "Man City", "T Hotspur"]
data = [[1, 2, 1],
        [0, 1, 0],
        [2, 4, 2]]

print_results_table(data, teams_list)

This will produce the following table:

            Man Utd  Man City T Hotspur
  Man Utd         1         2         1
 Man City         0         1         0
T Hotspur         2         4         2

If you want to have vertical line separators, you can replace " ".join with " | ".join.

References:

• lots about formatting https://pyformat.info/ (old and new formatting styles)
• the official Python tutorial (quite good) – https://docs.python.org/3/tutorial/inputoutput.html#the-string-format-method
• official Python information (can be difficult to read) – https://docs.python.org/3/library/string.html#string-formatting
• Another resource – https://www.python-course.eu/python3_formatted_output.php

I would try to loop through the list and use a CSV formatter to represent the data you want.

You can specify tabs, commas, or any other char as the delimiter.

Otherwise, just loop through the list and print “\t” after each element

http://docs.python.org/library/csv.html

I found this just looking for a way to output simple columns. If you just need no-fuss columns, then you can use this:

print("Titlex\tTitley\tTitlez")
for x, y, z in data:
    print(x, "\t", y, "\t", z)

EDIT: I was trying to be as simple as possible, and thereby did some things manually instead of using the teams list. To generalize to the OP’s actual question:

#Column headers
print("", end="\t")
for team in teams_list:
    print(" ", team, end="")
print()
# rows
for team, row in enumerate(data):
    teamlabel = teams_list[team]
    while len(teamlabel) < 9:
        teamlabel = " " + teamlabel
    print(teamlabel, end="\t")
    for entry in row:
        print(entry, end="\t")
    print()

Ouputs:

          Man Utd  Man City  T Hotspur
  Man Utd       1       2       1   
 Man City       0       1       0   
T Hotspur       2       4       2   

But this no longer seems any more simple than the other answers, with perhaps the benefit that it doesn’t require any more imports. But @campkeith’s answer already met that and is more robust as it can handle a wider variety of label lengths.