How can I pretty-print ASCII tables with Python?

Question:

I’m looking for a way to pretty-print tables like this:

=======================
| column 1 | column 2 |
=======================
| value1   | value2   |
| value3   | value4   |
=======================

I’ve found the asciitable library but it doesn’t do the borders, etc. I don’t need any complex formatting of data items, they’re just strings. I do need it to auto-size columns.

Do other libraries or methods exist, or do I need to spend a few minutes writing my own?

Asked By: kdt

||

Answers:

Here’s a quick and dirty little function I wrote for displaying the results from SQL queries I can only make over a SOAP API. It expects an input of a sequence of one or more namedtuples as table rows. If there’s only one record, it prints it out differently.

It is handy for me and could be a starting point for you:

def pprinttable(rows):
  if len(rows) > 1:
    headers = rows[0]._fields
    lens = []
    for i in range(len(rows[0])):
      lens.append(len(max([x[i] for x in rows] + [headers[i]],key=lambda x:len(str(x)))))
    formats = []
    hformats = []
    for i in range(len(rows[0])):
      if isinstance(rows[0][i], int):
        formats.append("%%%dd" % lens[i])
      else:
        formats.append("%%-%ds" % lens[i])
      hformats.append("%%-%ds" % lens[i])
    pattern = " | ".join(formats)
    hpattern = " | ".join(hformats)
    separator = "-+-".join(['-' * n for n in lens])
    print hpattern % tuple(headers)
    print separator
    _u = lambda t: t.decode('UTF-8', 'replace') if isinstance(t, str) else t
    for line in rows:
        print pattern % tuple(_u(t) for t in line)
  elif len(rows) == 1:
    row = rows[0]
    hwidth = len(max(row._fields,key=lambda x: len(x)))
    for i in range(len(row)):
      print "%*s = %s" % (hwidth,row._fields[i],row[i])

Sample output:

pkid                                 | fkn                                  | npi
-------------------------------------+--------------------------------------+----
405fd665-0a2f-4f69-7320-be01201752ec | 8c9949b9-552e-e448-64e2-74292834c73e | 0
5b517507-2a42-ad2e-98dc-8c9ac6152afa | f972bee7-f5a4-8532-c4e5-2e82897b10f6 | 0
2f960dfc-b67a-26be-d1b3-9b105535e0a8 | ec3e1058-8840-c9f2-3b25-2488f8b3a8af | 1
c71b28a3-5299-7f4d-f27a-7ad8aeadafe0 | 72d25703-4735-310b-2e06-ff76af1e45ed | 0
3b0a5021-a52b-9ba0-1439-d5aafcf348e7 | d81bb78a-d984-e957-034d-87434acb4e97 | 1
96c36bb7-c4f4-2787-ada8-4aadc17d1123 | c171fe85-33e2-6481-0791-2922267e8777 | 1
95d0f85f-71da-bb9a-2d80-fe27f7c02fe2 | 226f964c-028d-d6de-bf6c-688d2908c5ae | 1
132aa774-42e5-3d3f-498b-50b44a89d401 | 44e31f89-d089-8afc-f4b1-ada051c01474 | 1
ff91641a-5802-be02-bece-79bca993fdbc | 33d8294a-053d-6ab4-94d4-890b47fcf70d | 1
f3196e15-5b61-e92d-e717-f00ed93fe8ae | 62fa4566-5ca2-4a36-f872-4d00f7abadcf | 1

Example

>>> from collections import namedtuple
>>> Row = namedtuple('Row',['first','second','third'])
>>> data = Row(1,2,3)
>>> data
Row(first=1, second=2, third=3)
>>> pprinttable([data])
 first = 1
second = 2
 third = 3
>>> pprinttable([data,data])
first | second | third
------+--------+------
    1 |      2 |     3
    1 |      2 |     3
Answered By: MattH

For some reason when I included ‘docutils’ in my google searches I stumbled across texttable, which seems to be what I’m looking for.

Answered By: kdt

Version using w3m designed to handle the types MattH’s version accepts:

import subprocess
import tempfile
import html
def pprinttable(rows):
    esc = lambda x: html.escape(str(x))
    sour = "<table border=1>"
    if len(rows) == 1:
        for i in range(len(rows[0]._fields)):
            sour += "<tr><th>%s<td>%s" % (esc(rows[0]._fields[i]), esc(rows[0][i]))
    else:
        sour += "<tr>" + "".join(["<th>%s" % esc(x) for x in rows[0]._fields])
        sour += "".join(["<tr>%s" % "".join(["<td>%s" % esc(y) for y in x]) for x in rows])
    with tempfile.NamedTemporaryFile(suffix=".html") as f:
        f.write(sour.encode("utf-8"))
        f.flush()
        print(
            subprocess
            .Popen(["w3m","-dump",f.name], stdout=subprocess.PIPE)
            .communicate()[0].decode("utf-8").strip()
        )

from collections import namedtuple
Row = namedtuple('Row',['first','second','third'])
data1 = Row(1,2,3)
data2 = Row(4,5,6)
pprinttable([data1])
pprinttable([data1,data2])

results in:

┌───────┬─┐
│ first │1│
├───────┼─┤
│second │2│
├───────┼─┤
│ third │3│
└───────┴─┘
┌─────┬───────┬─────┐
│first│second │third│
├─────┼───────┼─────┤
│1    │2      │3    │
├─────┼───────┼─────┤
│4    │5      │6    │
└─────┴───────┴─────┘
Answered By: Janus Troelsen

I know it the question is a bit old but here’s my attempt at this:

https://gist.github.com/lonetwin/4721748

It is a bit more readable IMHO (although it doesn’t differentiate between single / multiple rows like @MattH’s solutions does, nor does it use NamedTuples).

Answered By: lonetwin

I’ve read this question long time ago, and finished writing my own pretty-printer for tables: tabulate.

My use case is:

  • I want a one-liner most of the time
  • which is smart enough to figure the best formatting for me
  • and can output different plain-text formats

Given your example, grid is probably the most similar output format:

from tabulate import tabulate
print tabulate([["value1", "value2"], ["value3", "value4"]], ["column 1", "column 2"], tablefmt="grid")
+------------+------------+
| column 1   | column 2   |
+============+============+
| value1     | value2     |
+------------+------------+
| value3     | value4     |
+------------+------------+

Other supported formats are plain (no lines), simple (Pandoc simple tables), pipe (like tables in PHP Markdown Extra), orgtbl (like tables in Emacs’ org-mode), rst (like simple tables in reStructuredText). grid and orgtbl are easily editable in Emacs.

Performance-wise, tabulate is slightly slower than asciitable, but much faster than PrettyTable and texttable.

P.S. I’m also a big fan of aligning numbers by a decimal column. So this is the default alignment for numbers if there are any (overridable).

Answered By: sastanin

I too wrote my own solution to this. I tried to keep it simple.

https://github.com/Robpol86/terminaltables

from terminaltables import AsciiTable
table_data = [
    ['Heading1', 'Heading2'],
    ['row1 column1', 'row1 column2'],
    ['row2 column1', 'row2 column2']
]
table = AsciiTable(table_data)
print table.table
+--------------+--------------+
| Heading1     | Heading2     |
+--------------+--------------+
| row1 column1 | row1 column2 |
| row2 column1 | row2 column2 |
+--------------+--------------+

table.inner_heading_row_border = False
print table.table
+--------------+--------------+
| Heading1     | Heading2     |
| row1 column1 | row1 column2 |
| row2 column1 | row2 column2 |
+--------------+--------------+

table.inner_row_border = True
table.justify_columns[1] = 'right'
table.table_data[1][1] += 'nnewline'
print table.table
+--------------+--------------+
| Heading1     |     Heading2 |
+--------------+--------------+
| row1 column1 | row1 column2 |
|              |      newline |
+--------------+--------------+
| row2 column1 | row2 column2 |
+--------------+--------------+
Answered By: Robpol86

Here’s my solution:

def make_table(columns, data):
    """Create an ASCII table and return it as a string.

    Pass a list of strings to use as columns in the table and a list of
    dicts. The strings in 'columns' will be used as the keys to the dicts in
    'data.'

    Not all column values have to be present in each data dict.

    >>> print(make_table(["a", "b"], [{"a": "1", "b": "test"}]))
    | a | b    |
    |----------|
    | 1 | test |
    """
    # Calculate how wide each cell needs to be
    cell_widths = {}
    for c in columns:
        values = [str(d.get(c, "")) for d in data]
        cell_widths[c] = len(max(values + [c]))

    # Used for formatting rows of data
    row_template = "|" + " {} |" * len(columns)

    # CONSTRUCT THE TABLE

    # The top row with the column titles
    justified_column_heads = [c.ljust(cell_widths[c]) for c in columns]
    header = row_template.format(*justified_column_heads)
    # The second row contains separators
    sep = "|" + "-" * (len(header) - 2) + "|"
    # Rows of data
    rows = []
    for d in data:
        fields = [str(d.get(c, "")).ljust(cell_widths[c]) for c in columns]
        row = row_template.format(*fields)
        rows.append(row)

    return "n".join([header, sep] + rows)
Answered By: Luke Taylor

I use this small utility function.

def get_pretty_table(iterable, header):
    max_len = [len(x) for x in header]
    for row in iterable:
        row = [row] if type(row) not in (list, tuple) else row
        for index, col in enumerate(row):
            if max_len[index] < len(str(col)):
                max_len[index] = len(str(col))
    output = '-' * (sum(max_len) + 1) + 'n'
    output += '|' + ''.join([h + ' ' * (l - len(h)) + '|' for h, l in zip(header, max_len)]) + 'n'
    output += '-' * (sum(max_len) + 1) + 'n'
    for row in iterable:
        row = [row] if type(row) not in (list, tuple) else row
        output += '|' + ''.join([str(c) + ' ' * (l - len(str(c))) + '|' for c, l in zip(row, max_len)]) + 'n'
    output += '-' * (sum(max_len) + 1) + 'n'
    return output

print get_pretty_table([[1, 2], [3, 4]], ['header 1', 'header 2'])

output

-----------------
|header 1|header 2|
-----------------
|1       |2       |
|3       |4       |
-----------------
Answered By: thavan

If you want a table with column and row spans, then try my library dashtable

from dashtable import data2rst

table = [
        ["Header 1", "Header 2", "Header3", "Header 4"],
        ["row 1", "column 2", "column 3", "column 4"],
        ["row 2", "Cells span columns.", "", ""],
        ["row 3", "Cellsnspan rows.", "- Cellsn- containn- blocks", ""],
        ["row 4", "", "", ""]
    ]

# [Row, Column] pairs of merged cells
span0 = ([2, 1], [2, 2], [2, 3])
span1 = ([3, 1], [4, 1])
span2 = ([3, 3], [3, 2], [4, 2], [4, 3])

my_spans = [span0, span1, span2]

print(data2rst(table, spans=my_spans, use_headers=True))

Which outputs:

+----------+------------+----------+----------+
| Header 1 | Header 2   | Header3  | Header 4 |
+==========+============+==========+==========+
| row 1    | column 2   | column 3 | column 4 |
+----------+------------+----------+----------+
| row 2    | Cells span columns.              |
+----------+----------------------------------+
| row 3    | Cells      | - Cells             |
+----------+ span rows. | - contain           |
| row 4    |            | - blocks            |
+----------+------------+---------------------+
Answered By: dmodo

You can try BeautifulTable. It does what you want to do. Here’s an example from it’s documentation

>>> from beautifultable import BeautifulTable
>>> table = BeautifulTable()
>>> table.columns.header = ["name", "rank", "gender"]
>>> table.rows.append(["Jacob", 1, "boy"])
>>> table.rows.append(["Isabella", 1, "girl"])
>>> table.rows.append(["Ethan", 2, "boy"])
>>> table.rows.append(["Sophia", 2, "girl"])
>>> table.rows.append(["Michael", 3, "boy"])
>>> print(table)
+----------+------+--------+
|   name   | rank | gender |
+----------+------+--------+
|  Jacob   |  1   |  boy   |
+----------+------+--------+
| Isabella |  1   |  girl  |
+----------+------+--------+
|  Ethan   |  2   |  boy   |
+----------+------+--------+
|  Sophia  |  2   |  girl  |
+----------+------+--------+
| Michael  |  3   |  boy   |
+----------+------+--------+
Answered By: Priyam Singh

This can be done with only builtin modules fairly compactly using list and string comprehensions. Accepts a list of dictionaries all of the same format…

def tableit(dictlist):
    lengths = [ max(map(lambda x:len(x.get(k)), dictlist) + [len(k)]) for k in dictlist[0].keys() ]
    lenstr = " | ".join("{:<%s}" % m for m in lengths)
    lenstr += "n"

    outmsg = lenstr.format(*dictlist[0].keys())
    outmsg += "-" * (sum(lengths) + 3*len(lengths))
    outmsg += "n"
    outmsg += "".join(
        lenstr.format(*v) for v in [ item.values() for item in dictlist ]
    )
    return outmsg
Answered By: MattK
from sys import stderr, stdout    
def create_table(table: dict, full_row: bool = False) -> None:

        min_len = len(min((v for v in table.values()), key=lambda q: len(q)))
        max_len = len(max((v for v in table.values()), key=lambda q: len(q)))

        if min_len < max_len:
            stderr.write("Table is out of shape, please make sure all columns have the same length.")
            stderr.flush()
            return

        additional_spacing = 1

        heading_separator = '| '
        horizontal_split = '| '

        rc_separator = ''
        key_list = list(table.keys())
        rc_len_values = []
        for key in key_list:
            rc_len = len(max((v for v in table[key]), key=lambda q: len(str(q))))
            rc_len_values += ([rc_len, [key]] for n in range(len(table[key])))

            heading_line = (key + (" " * (rc_len + (additional_spacing + 1)))) + heading_separator
            stdout.write(heading_line)

            rc_separator += ("-" * (len(key) + (rc_len + (additional_spacing + 1)))) + '+-'

            if key is key_list[-1]:
                stdout.flush()
                stdout.write('n' + rc_separator + 'n')

        value_list = [v for vl in table.values() for v in vl]

        aligned_data_offset = max_len

        row_count = len(key_list)

        next_idx = 0
        newline_indicator = 0
        iterations = 0

        for n in range(len(value_list)):
            key = rc_len_values[next_idx][1][0]
            rc_len = rc_len_values[next_idx][0]

            line = ('{:{}} ' + " " * len(key)).format(value_list[next_idx], str(rc_len + additional_spacing)) + horizontal_split

            if next_idx >= (len(value_list) - aligned_data_offset):
                next_idx = iterations + 1
                iterations += 1
            else:
                next_idx += aligned_data_offset

            if newline_indicator >= row_count:
                if full_row:
                    stdout.flush()
                    stdout.write('n' + rc_separator + 'n')
                else:
                    stdout.flush()
                    stdout.write('n')

                newline_indicator = 0

            stdout.write(line)
            newline_indicator += 1

        stdout.write('n' + rc_separator + 'n')
        stdout.flush()

Example:

table = {
        "uid": ["0", "1", "2", "3"],
        "name": ["Jon", "Doe", "Lemma", "Hemma"]
    }

create_table(table)

Output:

uid   | name       | 
------+------------+-
0     | Jon        | 
1     | Doe        | 
2     | Lemma      | 
3     | Hemma      | 
------+------------+-
Answered By: Lepstr

I just released termtables for this purpose. For example, this

import termtables as tt

tt.print(
    [[1, 2, 3], [613.23236243236, 613.23236243236, 613.23236243236]],
    header=["a", "bb", "ccc"],
    style=tt.styles.ascii_thin_double,
    padding=(0, 1),
    alignment="lcr"
)

gets you

+-----------------+-----------------+-----------------+
| a               |       bb        |             ccc |
+=================+=================+=================+
| 1               |        2        |               3 |
+-----------------+-----------------+-----------------+
| 613.23236243236 | 613.23236243236 | 613.23236243236 |
+-----------------+-----------------+-----------------+

By default, the table is rendered with Unicode box-drawing characters,

┌─────────────────┬─────────────────┬─────────────────┐
│ a               │       bb        │             ccc │
╞═════════════════╪═════════════════╪═════════════════╡
│ 1               │        2        │               3 │
├─────────────────┼─────────────────┼─────────────────┤
│ 613.23236243236 │ 613.23236243236 │ 613.23236243236 │
└─────────────────┴─────────────────┴─────────────────┘

termtables are very configurable; check out the tests for more examples.

Answered By: Nico Schlömer
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