Retrieve recognised text from JSON returned by Microsoft OCR

Question

The Microsoft OCR API returns json, and if I want to extact the text data from this json:

response = \
{
  "language": "en",
  "textAngle": -2.0000000000000338,
  "orientation": "Up",
  "regions": [
    {
      "boundingBox": "462,379,497,258",
      "lines": [
        {
          "boundingBox": "462,379,497,74",
          "words": [
            {
              "boundingBox": "462,379,41,73",
              "text": "A"
            },
            {
              "boundingBox": "523,379,153,73",
              "text": "GOAL"
            },
            {
              "boundingBox": "694,379,265,74",
              "text": "WITHOUT"
            }
          ]
        },
        {
          "boundingBox": "565,471,289,74",
          "words": [
            {
              "boundingBox": "565,471,41,73",
              "text": "A"
            },
            {
              "boundingBox": "626,471,150,73",
              "text": "PLAN"
            },
            {
              "boundingBox": "801,472,53,73",
              "text": "IS"
            }
          ]
        },
        {
          "boundingBox": "519,563,375,74",
          "words": [
            {
              "boundingBox": "519,563,149,74",
              "text": "JUST"
            },
            {
              "boundingBox": "683,564,41,72",
              "text": "A"
            },
            {
              "boundingBox": "741,564,153,73",
              "text": "WISH"
            }
          ]
        }
      ]
    }
  ]
}

def check_for_word(ocr):
    # Initialise our subject to None
    print("OCR: {}".format(ocr))
    subject = None
    for region in ocr["regions"]:
        if "lines" in region:
          for lines in region["lines"]:
            if "words" in lines:
              for word in lines["words"]:
                if "text" in word:
                  subject = word["text"].lower()
                  break

    print("OCR word is {}".format(subject))
    return subject

print(response["regions"][0]["lines"][0]["words"][0]["text"]) # Should return this

print(check_for_word(response))

• Each dictionary has arrays and we are unsure if the array contains any element
• Also not sure if the dictionary has key

Let's say we just wish to return the first text it matched from the image file.

This code works but it has a deep nested structure that has bad smell. Is there a better practice to write this in a cleaner way?

Answer 1

One way to almost halve the number of lines (and levels of indentation) needed is to use dict.get with [] as the optional default option:

def check_for_word(ocr):
    for region in ocr["regions"]:
        for lines in region.get("lines", []):
            for word in lines.get("words", []):
                if "text" in word:
                    return word["text"].lower()
    else:
        raise KeyError("OCR word not found")

I would also move the printing outside the function, so you can immediately return and add a else clause to catch the case that it is not present (this part could also be done outside with your code by checking for None).