NumPy: Pretty print tabular data
Solution 1
I seem to be having good output with prettytable:
from prettytable import PrettyTable
x = PrettyTable(dat.dtype.names)
for row in dat:
x.add_row(row)
# Change some column alignments; default was 'c'
x.align['column_one'] = 'r'
x.align['col_two'] = 'r'
x.align['column_3'] = 'l'
And the output is not bad. There is even a border
switch, among a few other options:
>>> print(x)
+------------+---------+-------------+
| column_one | col_two | column_3 |
+------------+---------+-------------+
| 0 | 0.0001 | ABCD |
| 1 | 1e-05 | ABCD |
| 2 | 1e-06 | long string |
| 3 | 1e-07 | ABCD |
+------------+---------+-------------+
>>> print(x.get_string(border=False))
column_one col_two column_3
0 0.0001 ABCD
1 1e-05 ABCD
2 1e-06 long string
3 1e-07 ABCD
Solution 2
The tabulate
package works nicely for Numpy arrays:
import numpy as np
from tabulate import tabulate
m = np.array([[1, 2, 3], [4, 5, 6]])
headers = ["col 1", "col 2", "col 3"]
# tabulate data
table = tabulate(m, headers, tablefmt="fancy_grid")
# output
print(table)
(Above code is Python 3; for Python 2 add from __future__ import print_function
at top of script)
Output:
╒═════════╤═════════╤═════════╕
│ col 1 │ col 2 │ col 3 │
╞═════════╪═════════╪═════════╡
│ 1 │ 2 │ 3 │
├─────────┼─────────┼─────────┤
│ 4 │ 5 │ 6 │
╘═════════╧═════════╧═════════╛
The package installs via pip
:
$ pip install tabulate # (use pip3 for Python 3 on some systems)
Solution 3
you can take advantage of array comprehension and use printf format strings:
for c1, c2, c3 in dat:
print "%2f | %8e | %s" % (c1, c2, c3)
https://en.wikipedia.org/wiki/Printf_format_string
And you can get even more customized if you go up to version 2.7
Solution 4
You might want to check out Pandas which has a lot of nice features for dealing with tabular data and seems to lay things out better when printing (It is designed be a python replacement for R):
Mike T
Hydrogeologist, numerical modeller and GIS professional. My main programming languages that I use are Python, R, SQL. I dabble with Fortran and C/C++/C# on occasions. Thanks to anyone that has helped me!
Updated on July 11, 2022Comments
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Mike T almost 2 years
I would like to print NumPy tabular array data, so that it looks nice. R and database consoles seem to demonstrate good abilities to do this. However, NumPy's built-in printing of tabular arrays looks like garbage:
import numpy as np dat_dtype = { 'names' : ('column_one', 'col_two', 'column_3'), 'formats' : ('i', 'd', '|U12')} dat = np.zeros(4, dat_dtype) dat['column_one'] = range(4) dat['col_two'] = 10**(-np.arange(4, dtype='d') - 4) dat['column_3'] = 'ABCD' dat['column_3'][2] = 'long string' print(dat) # [(0, 1.e-04, 'ABCD') (1, 1.e-05, 'ABCD') (2, 1.e-06, 'long string') # (3, 1.e-07, 'ABCD')]
I would like something that looks more like what a database spits out, for example, postgres-style:
column_one | col_two | column_3 ------------+---------+------------- 0 | 0.0001 | ABCD 1 | 1e-05 | ABCD 2 | 1e-08 | long string 3 | 1e-07 | ABCD
Are there any good third-party Python libraries to format nice looking ASCII tables?