Python accessing data in JSON object

Question

so I do this in my script: ``` import json info = json.loads(get_info()) print info ``` Which outputs: ``` richard@richard-desktop:~/projects/hello-python$ python main.py { "streams": [ { "index": 0, "codec_name": "mpeg2video", "codec_long_name": "MPEG-2 video", "codec_type": "video", "codec_time_base": "1001/48000", "codec_tag_string": "[0][0][0][0]", "codec_tag": "0x0000", "width": 1920, "height": 1080, "has_b_frames": 1, "sample_aspect_ratio": "1:1", "display_aspect_ratio": "16:9", "pix_fmt": "yuv422p", "level": 2, "timecode": "00:59:59:00", "id": "0x1e0", "r_frame_rate": "24000/1001", "avg_frame_rate": "10000/417", "time_base": "1/90000", "start_time": "0.945411" }, { "index": 1, "codec_name": "pcm_dvd", "codec_long_name": "PCM signed 20|24-bit big-endian", "codec_type": "audio", "codec_time_base": "1/48000", "codec_tag_string": "[0][0][0][0]", "codec_tag": "0x0000", "sample_fmt": "s32", "sample_rate": "48000", "channels": 2, "bits_per_sample": 0, "id": "0xa0", "r_frame_rate": "0/…

Accepted Answer

The JSON was encoded twice, and the result of `json.loads` is a string. Strings in python are sequences thus the first character is a `{`.

Decode the item again:

```
info = json.loads(json.loads(get_info()))
```

Now your main.py output should look like:

```
>>> result = json.loads(output)
>>> print result
{u'streams': [{u'pix_fmt': u'yuv422p', u'index': 0, u'start_time': u'0.945411', u'codec_tag': u'0x0000', u'sample_aspect_ratio': u'1:1', u'level': 2, u'r_frame_rate': u'24000/1001', u'id': u'0x1e0', u'time_base': u'1/90000', u'codec_tag_string': u'[0][0][0][0]', u'codec_type': u'video', u'has_b_frames': 1, u'width': 1920, u'codec_long_name': u'MPEG-2 video', u'display_aspect_ratio': u'16:9', u'codec_name': u'mpeg2video', u'timecode': u'00:59:59:00', u'height': 1080, u'codec_time_base': u'1001/48000', u'avg_frame_rate': u'10000/417'}, {u'index': 1, u'sample_fmt': u's32', u'codec_tag': u'0x0000', u'bits_per_sample': 0, u'r_frame_rate': u'0/0', u'start_time': u'0.945411', u'time_base': u'1/90000', u'codec_tag_string': u'[0][0][0][0]', u'codec_type': u'audio', u'channels': 2, u'duration': u'600.595000', u'codec_long_name': u'PCM signed 20|24-bit big-endian', u'codec_name': u'pcm_dvd', u'id': u'0xa0', u'sample_rate': u'48000', u'codec_time_base': u'1/48000', u'avg_frame_rate': u'0/0'}], u'format': {u'nb_streams': 2, u'start_time': u'0.945411', u'format_long_name': u'MPEG-PS format', u'format_name': u'mpeg', u'filename': u'/home/richard/projects/hello-python/tests/test_1.mpg', u'bit_rate': u'53723272', u'duration': u'600.595000', u'size': u'4033241092'}}
```

and you can access the streams and format parameters by name:

```
>>> result['streams']
[{u'pix_fmt': u'yuv422p', u'index': 0, u'start_time': u'0.945411', u'codec_tag': u'0x0000', u'sample_aspect_ratio': u'1:1', u'level': 2, u'r_frame_rate': u'24000/1001', u'id': u'0x1e0', u'time_base': u'1/90000', u'codec_tag_string': u'[0][0][0][0]', u'codec_type': u'video', u'has_b_frames': 1, u'width': 1920, u'codec_long_name': u'MPEG-2 video', u'display_aspect_ratio': u'16:9', u'codec_name': u'mpeg2video', u'timecode': u'00:59:59:00', u'height': 1080, u'codec_time_base': u'1001/48000', u'avg_frame_rate': u'10000/417'}, {u'index': 1, u'sample_fmt': u's32', u'codec_tag': u'0x0000', u'bits_per_sample': 0, u'r_frame_rate': u'0/0', u'start_time': u'0.945411', u'time_base': u'1/90000', u'codec_tag_string': u'[0][0][0][0]', u'codec_type': u'audio', u'channels': 2, u'duration': u'600.595000', u'codec_long_name': u'PCM signed 20|24-bit big-endian', u'codec_name': u'pcm_dvd', u'id': u'0xa0', u'sample_rate': u'48000', u'codec_time_base': u'1/48000', u'avg_frame_rate': u'0/0'}]
```

Pro tip: use the `pprint` module to format python structures nicely:

```
>>> from pprint import pprint
>>> print pprint(result)
>>> pprint(result)
{u'format': {u'bit_rate': u'53723272',
             u'duration': u'600.595000',
             u'filename': u'/home/richard/projects/hello-python/tests/test_1.mpg',
             u'format_long_name': u'MPEG-PS format',
             u'format_name': u'mpeg',
             u'nb_streams': 2,
             u'size': u'4033241092',
             u'start_time': u'0.945411'},
 u'streams': [{u'avg_frame_rate': u'10000/417',
               u'codec_long_name': u'MPEG-2 video',
               u'codec_name': u'mpeg2video',
               u'codec_tag': u'0x0000',
               u'codec_tag_string': u'[0][0][0][0]',
               u'codec_time_base': u'1001/48000',
               u'codec_type': u'video',
               u'display_aspect_ratio': u'16:9',
               u'has_b_frames': 1,
               u'height': 1080,
               u'id': u'0x1e0',
               u'index': 0,
               u'level': 2,
               u'pix_fmt': u'yuv422p',
               u'r_frame_rate': u'24000/1001',
               u'sample_aspect_ratio': u'1:1',
               u'start_time': u'0.945411',
               u'time_base': u'1/90000',
               u'timecode': u'00:59:59:00',
               u'width': 1920},
              {u'avg_frame_rate': u'0/0',
               u'bits_per_sample': 0,
               u'channels': 2,
               u'codec_long_name': u'PCM signed 20|24-bit big-endian',
               u'codec_name': u'pcm_dvd',
               u'codec_tag': u'0x0000',
               u'codec_tag_string': u'[0][0][0][0]',
               u'codec_time_base': u'1/48000',
               u'codec_type': u'audio',
               u'duration': u'600.595000',
               u'id': u'0xa0',
               u'index': 1,
               u'r_frame_rate': u'0/0',
               u'sample_fmt': u's32',
               u'sample_rate': u'48000',
               u'start_time': u'0.945411',
               u'time_base': u'1/90000'}]}
```

Python accessing data in JSON object

Solution

Problem