@ -351,8 +351,9 @@ Say you extracted a list of thumbnails into `thumbnail_data` and want to iterate
```python
```python
thumbnail_data = data.get('thumbnails') or []
thumbnail_data = data.get('thumbnails') or []
thumbnails = [{
thumbnails = [{
'url': item['url']
'url': item['url'],
} for item in thumbnail_data] # correct
'height': item.get('h'),
} for item in thumbnail_data if item.get('url')] # correct
```
```
and not like:
and not like:
@ -360,12 +361,27 @@ and not like:
```python
```python
thumbnail_data = data.get('thumbnails')
thumbnail_data = data.get('thumbnails')
thumbnails = [{
thumbnails = [{
'url': item['url']
'url': item['url'],
'height': item.get('h'),
} for item in thumbnail_data] # incorrect
} for item in thumbnail_data] # incorrect
```
```
In this case, `thumbnail_data` will be `None` if the field was not found and this will cause the loop `for item in thumbnail_data` to raise a fatal error. Using `or []` avoids this error and results in setting an empty list in `thumbnails` instead.
In this case, `thumbnail_data` will be `None` if the field was not found and this will cause the loop `for item in thumbnail_data` to raise a fatal error. Using `or []` avoids this error and results in setting an empty list in `thumbnails` instead.
Alternately, this can be further simplified by using `traverse_obj`
```python
thumbnails = [{
'url': item['url'],
'height': item.get('h'),
} for item in traverse_obj(data, ('thumbnails', lambda _, v: v['url']))]
pukkandan
2 years ago