CODEWITHSUNDEEP
pythonjson
Chris
Chris

Reputation: 409

How do I serialise JSON keys in a Python list?

I want to iterate through a JSON file using Python and print the a set of keys.

For example:

import json

KEYS_TO_PRINT = ["id", "channel.title"]
my_data = {"items": [{"id": 1, "channel": {"channelid": "channelid1", "title": "nailed_it1"}}, {"id": 2, "channel": {"channelid": "channelid2", "title": "nailed_it2"}}]}
this_row = []

for item in my_data["items"]:
    for key in KEYS_TO_PRINT:
        try:
            if "." in key:
                split_up = key.split(".")
                print item[split_up[0]][split_up[1]]
            else:
                print item[key]
        except KeyError:
            print "Oops"

However, it's pretty ugly. Is there a neater way?

Upvotes: 1

Views: 148

Answers (1)

Alex Sherman
Alex Sherman

Reputation: 524

Consider something like this, you can specify a subkey using "." to delimit your keys. Here's an example:

KEYS_TO_EXPORT = ["id", "dateTime", "title", "channel.title"]
item = {"id": 1, "channel": {"title": "nailed_it"}}
this_row = []
for export_key in KEYS_TO_EXPORT:
    try:
        value = item
        for key in export_key.split("."):
            value = value[key]
        this_row.append(str(value).encode('utf-8'))
    except KeyError:
        this_row.append("")

Edit to work with list:

This solution can easily be extended to work with a list of items as per the edit to the original question as follows. Also I switched to using .get like Will suggested in the comments.

KEYS_TO_PRINT = ["id", "channel.title"]
my_data = {"items": [
    {"id": 1, "channel": {"channelid": "channelid1", "title": "nailed_it1"}},
    {"id": 2, "channel": {"channelid": "channelid2", "title": "nailed_it2"}},
    {"id": 3}
]}
this_row = []

for item in my_data["items"]:
    for export_key in KEYS_TO_PRINT:
        value = item
        for key in export_key.split("."):
            value = value.get(key)
            if value == None: break
        this_row.append(str(value).encode('utf-8') if value != None else "")
print this_row

Upvotes: 2

Related Questions