how to print recursively a Python dictionary and its subdictionaries with whitespace alignment into columns - dictionary

Question

I want to create a function that can take a dictionary of dictionaries such as the following
information = {
"sample information": {
"ID": 169888,
"name": "ttH",
"number of events": 124883,
"cross section": 0.055519,
"k factor": 1.0201,
"generator": "pythia8",
"variables": {
"trk_n": 147,
"zappo_n": 9001
}
}
}
and then print it in a neat way such as the following, with alignment of keys and values using whitespace:
sample information:
ID: 169888
name: ttH
number of events: 124883
cross section: 0.055519
k factor: 1.0201
generator: pythia8
variables:
trk_n: 147
zappo_n: 9001
My attempt at the function is the following:
def printDictionary(
dictionary = None,
indentation = ''
):
for key, value in dictionary.iteritems():
if isinstance(value, dict):
print("{indentation}{key}:".format(
indentation = indentation,
key = key
))
printDictionary(
dictionary = value,
indentation = indentation + ' '
)
else:
print(indentation + "{key}: {value}".format(
key = key,
value = value
))
It produces the output like the following:
sample information:
name: ttH
generator: pythia8
cross section: 0.055519
variables:
zappo_n: 9001
trk_n: 147
number of events: 124883
k factor: 1.0201
ID: 169888
As is shown, it successfully prints the dictionary of dictionaries recursively, however is does not align the values into a neat column. What would be some reasonable way of doing this for dictionaries of arbitrary depth?

Answer 1

Try using the pprint module. Instead of writing your own function, you can do this:
import pprint
pprint.pprint(my_dict)
Be aware that this will print characters such as { and } around your dictionary and [] around your lists, but if you can ignore them, pprint() will take care of all the nesting and indentation for you.