JSONDecodeError when using for loop in python

Question

I've been trying to do some API queries to get some missing data in my DF. I'm using grequest library to send multiple request and create a list for the response object. Then I use a for loop to load the response in a json to retrieve the missing data. What I noticed is that when loading the data using .json() from the list directly using notition list[0].json() it works fine, but when trying to read the list and then load the response into a json, This error comes up : JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Here's my code :

import requests 
import json
import grequests

ls = []
for i in null_data['name']:
    url = 'https://pokeapi.co/api/v2/pokemon/' + i.lower()
    ls.append(url)
rs  = (grequests.get(u) for u in ls)
s = grequests.map(rs)
#This line works
print(s[0].json()['weight']/10)

for x in s:
    #This one fails
    js = x.json()
    peso = js['weight']/10
    null_data.loc[null_data['name'] == i.capitalize(), 'weight_kg'] = peso

<ipython-input-21-9f404bc56f66> in <module>
     13 
     14 for x in s:
---> 15     js = x.json()
     16     peso = js['weight']/10
     17     null_data.loc[null_data['name'] == i.capitalize(), 'weight_kg'] = peso

JSONDecodeError: Expecting value: line 1 column 1 (char 0)

score 0 · Accepted Answer · answered Feb 27 '21 at 15:26

One (or more) elements are empty.

So:

...
for x in s:
    if x != ""
        js = x.json()
        peso = js['weight']/10
        null_data.loc[null_data['name'] == i.capitalize(), 'weight_kg'] = peso
...

or

...
for x in s:
    try:
        js = x.json()
        peso = js['weight']/10
        null_data.loc[null_data['name'] == i.capitalize(), 'weight_kg'] = peso
    except json.JSONDecodeError as ex: print("Failed to decode(%s)"%ex)
...

The first checks if x is an empty string while the other tries to decode every one but upon an exception just prints an error message instead of quitting.

JSONDecodeError when using for loop in python

1 Answers1