When passing a list to an api I get the following error code "json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)"

Question

So I have been working on creating a mini pokedex using the poke api and I am stuck in a step.

This is what I have:

import requests
import json
import pandas as pd

pokemon_list = ["charizard", "gengar", "venusaur","golbat","gyarados","lapras", "dragonite", "infernape", "staraptor", "giratina"]
# Create empty lists to append all data:
name, height, weight = [],[],[]


# Get data from API
for pokemon in pokemon_list:
    res = requests.get(f"https://pokeapi.co/api/v2/pokemon/{pokemon}/")
    pokedata = json.loads(res.text)
    # Append data to the list:
    name.append(pokedata["name"])
    height.append(pokedata["height"])
    weight.append(pokedata["weight"])

ddata = {"Name": name, "Height": height, "Weight": weight} 
df_data = pd.DataFrame(ddata)
print(df_data)

and this is the TraceBack I am getting:

Traceback (most recent call last):
  File "main.py", line 19, in <module>
    pokedata = json.loads(res.text)
  File "/nix/store/2vm88xw7513h9pyjyafw32cps51b0ia1-python3-3.8.12/lib/python3.8/json/__init__.py", line 357, in loads
    return _default_decoder.decode(s)
  File "/nix/store/2vm88xw7513h9pyjyafw32cps51b0ia1-python3-3.8.12/lib/python3.8/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/nix/store/2vm88xw7513h9pyjyafw32cps51b0ia1-python3-3.8.12/lib/python3.8/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
 

P.S.: if I try to read just one pokemon instead of a list, it works fine, but whenever I try to use a list with the for loop, I get this error. Any help you guys can provide will be greatly appreciated.

Answer 1

It turns out res.text is 'Not Found' in the failing case. Don't try to read the JSON if the result fails. FYI, debug yourself by print(res.text) before the line that fails.

import requests
import json
import pandas as pd

pokemon_list = ["charizard", "gengar", "venusaur","golbat","gyarados","lapras", "dragonite", "infernape", "staraptor", "giratina"]
#Create empty lists to append all data:
name, height, weight = [],[],[]

#Get data from API
for pokemon in pokemon_list:
    res = requests.get(f"https://pokeapi.co/api/v2/pokemon/{pokemon}/")
    if res.ok:
        pokedata = res.json()
        # Append data to the list:
        name.append(pokedata["name"])
        height.append(pokedata["height"])
        weight.append(pokedata["weight"])
    else:
        print(f'{pokemon} not found')

ddata = {"Name": name, "Height": height, "Weight": weight} 
df_data = pd.DataFrame(ddata)
print(df_data)

Output:

giratina not found
        Name  Height  Weight
0  charizard      17     905
1     gengar      15     405
2   venusaur      20    1000
3     golbat      16     550
4   gyarados      65    2350
5     lapras      25    2200
6  dragonite      22    2100
7  infernape      12     550
8  staraptor      12     249