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Python JSON

Brett McGregor
Brett McGregor
Courses Plus Student 1,903 Points

read JSON file error: " list indices must be integers or slices, not str"

So, here is my code to read a JSON file.

import json

with open("example.json") as file:
    db = json.load(file)

and here is the JSON file I found to work with:

  "_id": {
    "$oid": "5968dd23fc13ae04d9000001"
  "product_name": "sildenafil citrate",
  "supplier": "Wisozk Inc",
  "quantity": 261,
  "unit_cost": "$10.47"
}, {
  "_id": {
    "$oid": "5968dd23fc13ae04d9000002"
  "product_name": "Mountain Juniperus ashei",
  "supplier": "Keebler-Hilpert",
  "quantity": 292,
  "unit_cost": "$8.74"
}, {
  "_id": {
    "$oid": "5968dd23fc13ae04d9000003"
  "product_name": "Dextromathorphan HBr",
  "supplier": "Schmitt-Weissnat",
  "quantity": 211,
  "unit_cost": "$20.53"

Python gives me the following error:

Traceback (most recent call last):
  File "C:/Python36-32/Scripts/read_JSON.py", line 5, in <module>
TypeError: list indices must be integers or slices, not str

My code is exactly the same as Kenneth used in the video. I guess the JSON file I am using is somehow different to the one Kenneth used in his example.

Brett McGregor
Brett McGregor
Courses Plus Student 1,903 Points

I have just noticed that my JSON file is enclosed in square brackets. I suppose that makes it a list, which explains my error.

I tried with a different JSON file and was able to return data.

I guess I need to learn more about this topic!!!

1 Answer

Oszkár Fehér
.a{fill-rule:evenodd;}techdegree seal-36
Oszkár Fehér
Treehouse Project Reviewer

Hi Brett. It gives you that error because when you print the "db" variable with the keyword "supplier" it looks in a dictionary


but "db" actually is a list, and on list you can use or integer or slices, like


where the number indicates the position of the item but if you cal


then it will look for the first item keyword "supplier" and gives you back one item. I checked for slices and i'm not sure why it gives error for slice for ex:


So the solution if you want all the suppliers from the json file you have to make a for loop on "db"

items = []
for item in db:


print([db_item["supplier"] for db_item in db])

And you get the desired result. I hope it helps you to understand. Happy coding