Question 214774 in Json Question posted in
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Loop over JSON arrays in python

I wanted to loop over a section in my JSON File and render the geometry based on their names in the File.
main.py

import json

data = json.load(open('src/test.json'))

for geo in data["geometry"]:
    if geo == "rect:
       Geometry.rectangle(draw=pen, x=geo["x"], y=geo["y"], width=geo["width"],
                       height=geo["height"], rgb=geo["color"]

src/test.py (a little simplified)

{
  "geometry": {
    "rect": {
      "x": 10,
      "y": 10,
      "width": 40,
      "heigth": 40,
      "color": {
        "r": 255,
        "g": 100,
        "b": 0
      }
    },
    "ellipse": {
      "x": 200,
      "y": 100,
      "width": 400,
      "heigth": 400,
      "color": {
        "r": 0,
        "g": 255,
        "b": 0
      }
    },
    "polygon": {
      "x": 200,
      "y": 100,
      "radius": 200,
      "sites": 8,
      "rotation": 90,
      "color": {
        "r": 0,
        "g": 255,
        "b": 0
      }
    },
    "text": {
      "x": 200,
      "y": 100,
      "size": 20,
      "text": "jklsajflksdjf",
      "words_per_line": 20,
      "id": "text_1",
      "align": "right",
      "color": {
        "r": 0,
        "g": 255,
        "b": 0
      },
      "font_style": "monospace"
    }
  }
}

everytime i execute this code, ill get this error:

print(geo["rect"])
          ^^^^^^^^^^
TypeError: string indices must be integers, not 'str'

I tried it with indexes, like geo[0] but it returned the first char of the string, "rect" -> "r" Is there a way to get the values from the geometry?

Tags:

2

Answers


  1. 0

    Once the json is loaded, it’s represented as a dictionary in python. Just looping over a dictionary in python you get the keys from the dictionary, so so far your code is correct:

    for geo in data["geometry"]:
    if geo == "rect":
        print("Rectangle")

    If you want to grab the data belonging to this geometry, you could ask the original data

    for geo in data["geometry"]:
    if geo == "rect":
        print("Rectangle", data["geometry"][geo])

    Or better, use the items() iterator that gives you the key and value directly as a tuple

    for geo_name, geo_data in data["geometry"].items():
    if geo_name == "rect":
        print("Rectangle", geo_data)
        Geometry.rectangle(draw=pen, x=geo_data["x"], y=geo_data["y"], width=geo_data["width"],
                           height=geo_data["height"], rgb=geo_data["color"]
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  2. 0

    Looking at your data I’d slightly restructure your script. Instead of looping and comparing strings you can use dict.get and check if the shape is there:

    import json

with open('your_data.json', 'r') as f_in:
    data = json.load(f_in)

geo = data['geometry']

# draw rect:
if (shape:=geo.get('rect')):
    print('Rect', shape['x'], shape['y'])

# draw ellipse
if (shape:=geo.get('ellipse')):
    print('Ellipse', shape['x'], shape['y'])

# ...

    Prints:

    Rect 10 10
Ellipse 200 100
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