Pretty print JSON dumps

I ended up using jsbeautifier:

import jsbeautifieropts = jsbeautifier.default_options()opts.indent_size = 2jsbeautifier.beautify(json.dumps(d), opts)

Output:

{  "a": "blah",  "c": [1, 2, 3],  "b": "foo"}

Write your own JSON serializer:

import numpyINDENT = 3SPACE = " "NEWLINE = "\n"def to_json(o, level=0):    ret = ""    if isinstance(o, dict):        ret += "{" + NEWLINE        comma = ""        for k,v in o.iteritems():            ret += comma            comma = ",\n"            ret += SPACE * INDENT * (level+1)            ret += '"' + str(k) + '":' + SPACE            ret += to_json(v, level + 1)        ret += NEWLINE + SPACE * INDENT * level + "}"    elif isinstance(o, basestring):        ret += '"' + o + '"'    elif isinstance(o, list):        ret += "[" + ",".join([to_json(e, level+1) for e in o]) + "]"    elif isinstance(o, bool):        ret += "true" if o else "false"    elif isinstance(o, int):        ret += str(o)    elif isinstance(o, float):        ret += '%.7g' % o    elif isinstance(o, numpy.ndarray) and numpy.issubdtype(o.dtype, numpy.integer):        ret += "[" + ','.join(map(str, o.flatten().tolist())) + "]"    elif isinstance(o, numpy.ndarray) and numpy.issubdtype(o.dtype, numpy.inexact):        ret += "[" + ','.join(map(lambda x: '%.7g' % x, o.flatten().tolist())) + "]"    else:        raise TypeError("Unknown type '%s' for json serialization" % str(type(o)))    return retinputJson = {'a': 'blah', 'b': 'foo', 'c': [1,2,3]}print to_json(inputJson)

Output:

{   "a": "blah",   "c": [1,2,3],   "b": "foo"}

Another alternative is print(json.dumps(d, indent=None, separators=(',\n', ': ')))

The output will be:

{"a": "blah","c": [1,2,3],"b": "foo"}

Note that though the official docs at https://docs.python.org/2.7/library/json.html#basic-usage say the default args are separators=None --that actually means "use default of separators=(', ',': ') ). Note also that the comma separator doesn't distinguish between k/v pairs and list elements.