Force a user to pass dictionary on command line

Question

I want to pass a dictionary on command line. The following code fails:

import json
import argparse

parser = argparse.ArgumentParser(description='Test Arg Parse')
parser.add_argument('-d', '--dict', type=dict, required=False)

variables = vars(parser.parse_args())
print json.dumps(variables)

When I'm running the program, it throws the following error:

C:\KTLO\bin>python TestProg.py -d "{'a':'b'}"
usage: TestProg.py [-h] [-d DICT]
TestProg.py: error: argument -d/--dict: invalid dict value: "{'a':'b'}"

Edit 1: Specifying 'json.loads' or 'dict' does not change the output and still it throws the error.

You need to make `json.loads` the `type`, it makes no sense as `default` and `dict` doesn't accept as string representation of a dictionary. — jonrsharpe, Jul 07 '16 at 10:17
@Siva In the accepted answer, it is showing a hack, which actually doesn't work. — Nitin Pandey, Jul 07 '16 at 10:18
Passing `json.loads` as `type` isn't a hack, and it does work. — jonrsharpe, Jul 07 '16 at 10:22
@jonrsharpe Yes. I copied the wrong code! Even with your suggested changes, it is throwing the same error. Can this be done? — Nitin Pandey, Jul 07 '16 at 10:23
@jonrsharpe It is not working for me. [code and output](http://hastebin.com/zejeqayife.tex). Can you share your version. — Nitin Pandey, Jul 07 '16 at 10:28
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/116670/discussion-between-psychocoder-and-jonrsharpe). — Nitin Pandey, Jul 07 '16 at 10:29
Put it *in the question*, please, not on some random off-site text dump. I have undeleted my answer, your problem appears to be that your input isn't valid JSON. Strings *must* be quoted, using `"`. — jonrsharpe, Jul 07 '16 at 11:00
@jonrsharpe I am able to run the above script on python 2.6.6. The same code throws an error on 2.7. — Nitin Pandey, Jul 07 '16 at 12:48

score 1 · Answer 1 · answered Jul 07 '16 at 10:13

1

Try

python TestProg.py -d '{"a":"b"}'

single quotes are no valid json.

answered Jul 07 '16 at 10:13

allo

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`C:\KTLO\bin>python TestProg.py -d '{"a":"b"}' usage: TestProg.py [-h] [-d DICT] TestProg.py: error: argument -d/--dict: invalid dict value: "'{a:b}'" ` Doesn't work – Nitin Pandey Jul 07 '16 at 10:16
1

i guess additional your ``default=`` should be ``type=``, see http://stackoverflow.com/a/18609361/893159 – allo Jul 07 '16 at 10:17
@psychoCoder note that you're quoting the whole object, not the keys and values in it. – jonrsharpe Jul 07 '16 at 11:14

Force a user to pass dictionary on command line

1 Answers1