Prettyprint to a file?

Question

I'm using this gist's tree, and now I'm trying to figure out how to prettyprint to a file. Any tips?

Is the output format somewhat relevant (other than being properly formatted)? — Stefano Sanfilippo, Jun 24 '13 at 16:38
@Stefano There are multiple keys and values, which should be clear in the format. — James.Wyst, Jun 24 '13 at 16:42
@MattBall If I printed it with a .write(), the output would essentially be all one line-utterly unreadable. — James.Wyst, Jun 24 '13 at 16:44

score 86 · Accepted Answer · answered Jun 24 '13 at 16:41

86

What you need is Pretty Print pprint module:

from pprint import pprint

# Build the tree somehow

with open('output.txt', 'wt') as out:
    pprint(myTree, stream=out)

answered Jun 24 '13 at 16:41

Stefano Sanfilippo

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Doesn't work anymore, it seems you need to pass stream in the constructor of pprint.PrettyPrinter() like so `pp = pprint.PrettyPrinter(stream=open("thing",'w'))` – jokoon Mar 25 '18 at 11:15
1

Not working with Python 3.6.5. The output is a list not a graph which is pretty printed on the screen. – Peter.k Feb 06 '19 at 18:03
2

Worked for me with Python 3.7.2. – Noumenon Jan 02 '20 at 20:02
Works fine for me in python 3.9 as well – Justin Furuness Jan 30 '22 at 06:48

GaryMBloom · Answer 2 · 2020-10-14T12:52:23.237

12

Another general-purpose alternative is Pretty Print's pformat() method, which creates a pretty string. You can then send that out to a file. For example:

import pprint
data = dict(a=1, b=2)
output_s = pprint.pformat(data)
#          ^^^^^^^^^^^^^^^
with open('output.txt', 'w') as file:
    file.write(output_s)

edited Oct 14 '20 at 12:52

answered Dec 05 '19 at 08:48

GaryMBloom

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Great, thanks, although I prefer: `with open('output.txt','w') as output: output.write(pprint.pformat(data))` – Andrew Oct 13 '20 at 10:59
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@Andrew - Absolutely! A good context block is always the best choice! I will update my answer to make it a better programming example. – GaryMBloom Oct 14 '20 at 12:46

score 0 · Answer 3 · edited Jan 30 '22 at 22:08

0

If I understand correctly, you just need to provide the file to the stream keyword on pprint:

from pprint import pprint

with open(outputfilename, 'w') as fout:
    pprint(tree, stream=fout, **other_kwargs)

edited Jan 30 '22 at 22:08

Justin Furuness

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answered Jun 24 '13 at 16:41

mgilson

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JGFMK · Answer 4 · 2021-05-16T20:30:32.583

import pprint
outf = open("./file_out.txt", "w")
PP = pprint.PrettyPrinter(indent=4,stream=outf)
d = {'a':1, 'b':2}
PP.pprint(d)
outf.close()

Could not get the stream= in the accepted answer to work without this syntax in Python 3.9. Hence the new answer. You could also improve on using the with syntax to improve on this too.

import pprint
d = {'a':1, 'b':2}
with open('./test2.txt', 'w+') as out:
    PP = pprint.PrettyPrinter(indent=4,stream=out)
    PP.pprint(d)

Prettyprint to a file?

4 Answers4

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