how can I convert a dictionary to a string of keyword arguments?

Question

we can convert the dictionary to kw using **kw but if I want kw as str(kw) not str(dict), as I want a string with keyword arguments for code_generator,

if I pass

obj.method(name='name', test='test', relation = [('id','=',1)])

I want a function to return the string like

"name='name', test='test', relation = [('id','=',1)]"

score 12 · Accepted Answer · edited Dec 16 '20 at 23:56

12

The same syntax is used to accept arbitrary keyword arguments.

Python 2:

def somestring(**kwargs):
  return ', '.join('%s=%r' % x for x in kwargs.iteritems())

Python 3:

def somestring(**kwargs):
    return ", ".join(f"{key}={value}" for key, value in kwargs.items())

Note that dicts are arbitrarily ordered, so the resultant string may be in a different order than the arguments passed.

edited Dec 16 '20 at 23:56

Richie Bendall

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answered May 10 '10 at 12:09

Ignacio Vazquez-Abrams

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3

Note `.iteritems()` is Python 2 syntax; in Python 3 it's `.items()`. See https://stackoverflow.com/a/10458567/4115031 – Nathan Wailes Apr 22 '19 at 05:02
2

Python3 update with use of f-strings: `", ".join(f'{x[0]}={x[1]!r}' for x in kwargs.items())` – James Owers Oct 02 '19 at 15:07
2

`", ".join(f"{key}={value}" for key, value in kwargs.items())` is maybe even more Pythonic. – cbrnr Jan 25 '20 at 09:28

score 1 · Answer 2 · answered Dec 21 '19 at 03:06

1

The upper answer can not run properly on python 2.7.16, it should be

def somestring(**kwargs):
    return ''.join([('%s=%s' % x) for x in kwargs.iteritems()]) 


#A full example:

def RunCommandAndEnsureZero(*args, **kwargs):
    retCode = RunCommand(*args, **kwargs)
    if retCode != 0:
        kwargsString = ''.join([('%s=%s' % x) for x in kwargs.iteritems()])
        raise Exception("error command: \"%s %s\"" % (''.join(args), kwargsString))

answered Dec 21 '19 at 03:06

Alen Wesker

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use [] to let the generator run; then use the ("%s=%s" %x) to format a proper string formatting; finally join them – Alen Wesker Dec 21 '19 at 03:07

how can I convert a dictionary to a string of keyword arguments?

2 Answers2