Pretty-print tabular data
Project description
Pretty-print tabular data in Python.
The main use cases of the library are:
printing small tables without hassle: just one function call, formatting is guided by the data itself
authoring tabular data for lightweight plain-text markup: multiple output formats suitable for further editing or transformation
readable presentation of mixed textual and numeric data: smart column alignment, configurable number formatting, alignment by a decimal point
Installation
pip install tabulate
Usage
The module provides just one function, tabulate, which takes a list of lists or a similarly shaped data structure, and outputs a nicely formatted plain-text table:
>>> from __future__ import print_function >>> from tabulate import tabulate >>> table = [["Sun",696000,1989100000],["Earth",6371,5973.6], ... ["Moon",1737,73.5],["Mars",3390,641.85]] >>> print(tabulate(table)) ----- ------ ------------- Sun 696000 1.9891e+09 Earth 6371 5973.6 Moon 1737 73.5 Mars 3390 641.85 ----- ------ -------------
tabulate can pretty-print two-dimensional NumPy arrays too.
Headers
If function tabulate receives two arguments, it considers the second argument to be a list of column headers. The list of headers may be passed also out-of-order with a named argument headers=...:
>>> print(tabulate(table, headers=["Planet","R (km)", "mass (x 10^29 kg)"])) Planet R (km) mass (x 10^29 kg) -------- -------- ------------------- Sun 696000 1.9891e+09 Earth 6371 5973.6 Moon 1737 73.5 Mars 3390 641.85
Table format
There is more than one way to format a table in plain text. The output format of tabulate is defined by an optional named argument tablefmt.
Supported table formats are:
“plain”
“simple”
“grid”
“pipe”
“orgtbl”
plain tables do not use any pseudo-graphics to draw lines:
>>> table = [["spam",42],["eggs",451],["bacon",0]] >>> headers = ["item", "qty"] >>> print(tabulate(table, headers, tablefmt="plain")) item qty spam 42 eggs 451 bacon 0
simple is the default format (the default may change in future versions). It corresponds to simple_tables in Pandoc Markdown extensions:
>>> print(tabulate(table, headers, tablefmt="simple")) item qty ------ ----- spam 42 eggs 451 bacon 0
grid is like tables formatted by Emacs’ table.el package. It corresponds to grid_tables in Pandoc Markdown extensions:
>>> print(tabulate(table, headers, tablefmt="grid")) +--------+-------+ | item | qty | +========+=======+ | spam | 42 | +--------+-------+ | eggs | 451 | +--------+-------+ | bacon | 0 | +--------+-------+
pipe follows the conventions of PHP Markdown Extra extension. It corresponds to pipe_tables in Pandoc. This format uses colons to indicate column alignment:
>>> print(tabulate(table, headers, tablefmt="pipe")) | item | qty | |:-------|------:| | spam | 42 | | eggs | 451 | | bacon | 0 |
orgtbl follows the conventions of Emacs org-mode, and is editable also in the minor orgtbl-mode. Hence its name:
>>> print(tabulate(table, headers, tablefmt="orgtbl")) | item | qty | |--------+-------| | spam | 42 | | eggs | 451 | | bacon | 0 |
Column alignment
tabulate is smart about column alignment. It detects columns which contain only numbers, and aligns them by a decimal point (or flushes them to the right if they appear to be integers). Text columns are flushed to the left.
You can override the default alignment with numalign and stralign named arguments. Possible column alignments are: right, center, left, decimal (only for numbers).
Aligning by a decimal point works best when you need to compare numbers at a glance:
>>> print(tabulate([[1.2345],[123.45],[12.345],[12345],[1234.5]])) ---------- 1.2345 123.45 12.345 12345 1234.5 ----------
Compare this with a more common right alignment:
>>> print(tabulate([[1.2345],[123.45],[12.345],[12345],[1234.5]], numalign="right")) ------ 1.2345 123.45 12.345 12345 1234.5 ------
For tabulate, anything which can be parsed as a number is a number. Even numbers represented as strings are aligned properly. This feature comes in handy when reading a mixed table of text and numbers from a file:
>>> import csv ; from StringIO import StringIO >>> table = list(csv.reader(StringIO("spam, 42\neggs, 451\n"))) >>> table [['spam', ' 42'], ['eggs', ' 451']] >>> print(tabulate(table)) ---- ---- spam 42 eggs 451 ---- ----
Number formatting
tabulate allows to define custom number formatting applied to all columns of decimal numbers. Use floatfmt named argument:
>>> print tabulate([["pi",3.141593],["e",2.718282]], floatfmt=".4f") -- ------ pi 3.1416 e 2.7183 -- ------
Performance considerations
Such features as decimal point alignment and trying to parse everything as a number imply that tabulate:
needs to keep the entire table in-memory
has to “transpose” the table twice
does much more work than it may appear
It may not be suitable to pretty-print really big tables (but who’s going to do that, anyway?) or printing tables in performance sensitive applications. tabulate is about two orders of magnitude slower than simply joining lists of values with a tab, coma or other separator.
A micro-benchmark in ipython to compare tabulate with CSV file generation, and simple formatting and joining cell values with a tab:
>>> # a test table with mixed textual and numeric data >>> table = [["some text"]+range(i,i+9) for i in range(10)] >>> # conversion to CSV >>> import csv ; from StringIO import StringIO >>> csv.writer(StringIO()).writerows(table) >>> # joining with tabs >>> def tabulate_fast(rows): ... return "\n".join(("\t".join(map(str,row)) for row in rows)) ...
The results:
method time (us) rel. time ----------------- ----------- ----------- csv to StringIO 30.80 1.33 joining with tabs 23.10 1.00 tabulate 853.00 36.93
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.