將double for循環轉換為列表理解

Question

我有以下json對象：

{u'trailerAvailable': False, u'number': 10, u'watched': False, u'starringCast': u'Jan Fedder,Anja Nejarri', u'genres': [u'Krimi'], u'title': u'S\xfc\xdfes Jenseits', u'ancestorTitles': [{u'contentType': u'SERIES', u'titleId': u'B00ILY1FWE', u'title': u'Gro\xdfstadtrevier'}, {u'contentType': u'SEASON', u'number': 19, u'titleId': u'B00ILZTVXI', u'title': u'Gro\xdfstadtrevier - Staffel 19'}], u'restricted': False, u'synopsis': u"Dirk Matthies und Katja Metz erhalten einen entscheidenden Tipp, um endlich Hannes Rogolski alias 'die Ziege' zu fassen. Allerdings bringt der schwer kranke Informant dadurch seine Lebensgef\xe4hrtin Hilde in Gefahr.", u'titleId': u'B00ILZOQWE', u'watchCompleted': False, u'creditsStartTimeMillis': 2836000, u'customerReviewsCollectionIncluded': True, u'contentType': u'EPISODE', u'childTitles': [], u'studioOrNetwork': u'ARD', u'amazonRating': {u'count': 0, u'rating': 0.0}, u'watchedPositionMillis': {u'valueMillis': 0}, u'listInfo': [], u'previewAvailable': False, u'subtitles': {u'content': {u'languages': []}, u'preview': {u'languages': []}, u'trailer': {u'languages': []}}, u'restrictions': [], u'regulatoryRating': u'12', u'releaseOrFirstAiringDate': {u'valueFormatted': u'2005-03-21T00:00:00', u'valueDate': 1111363200000000}, u'hasSubtitles': False, u'formats': [{u'hasMobileTrailerEncode': False, u'videoAspectRatio': 0.0, u'offers': [{u'asin': u'B0043YVHMY', u'offerType': u'SUBSCRIPTION', u'buyable': False}, {u'asin': u'B00ILZOQWE', u'price': {u'valueFormatted': u'1,49\u20ac', u'valueLong': 149.0}, u'offerType': u'PURCHASE', u'purchaseButtonText': u'Buy episode - 1,49\u20ac', u'buyable': True}, {u'rentalExpiryTermFromPurchase': {u'valueMillis': 2592000000, u'valueFormatted': u'30 days to start watching'}, u'asin': u'B00QVECS4U', u'rentalExpiryTermFromStart': {u'valueMillis': 86400000, u'valueFormatted': u'24 hours to complete watching'}, u'offerType': u'RENTAL', u'buyable': False}], u'audioFormatTypes': [u'STEREO'], u'videoFormatType': u'SD', u'hasMobileEncode': True, u'images': [{u'heightPx': 0, u'widthPx': 0, u'type': u'COVER_ART_TV', u'uri': u'http://ecx.images-amazon.com/images/I/51a8c53GcjL._UR667,500_V1_PJStripe-Prime-Only-500px,TopLeft,0,0_.jpg'}, {u'heightPx': 0, u'widthPx': 0, u'type': u'COVER_ART_TV', u'uri': u'http://ecx.images-amazon.com/images/I/51a8c53GcjL._UR667,500_V1_PJStripe-Prime-Only-500px,TopLeft,0,0_.jpg'}], u'hasTrailerEncode': False, u'hasEncode': True}, {u'hasMobileTrailerEncode': False, u'videoAspectRatio': 0.0, u'offers': [{u'asin': u'B0043YVHMY', u'offerType': u'SUBSCRIPTION', u'buyable': False}, {u'asin': u'B00ILZOR9Q', u'offerType': u'PURCHASE', u'buyable': False}, {u'rentalExpiryTermFromPurchase': {u'valueMillis': 2592000000, u'valueFormatted': u'30 days to start watching'}, u'asin': u'B00QVFSN0W', u'rentalExpiryTermFromStart': {u'valueMillis': 86400000, u'valueFormatted': u'24 hours to complete watching'}, u'offerType': u'RENTAL', u'buyable': False}], u'audioFormatTypes': [u'STEREO'], u'videoFormatType': u'HD', u'hasMobileEncode': False, u'images': [{u'heightPx': 0, u'widthPx': 0, u'type': u'COVER_ART_TV', u'uri': u'http://ecx.images-amazon.com/images/I/51a8c53GcjL._UR667,500_V1_PJStripe-Prime-Only-500px,TopLeft,0,0_.jpg'}, {u'heightPx': 0, u'widthPx': 0, u'type': u'COVER_ART_TV', u'uri': u'http://ecx.images-amazon.com/images/I/51a8c53GcjL._UR667,500_V1_PJStripe-Prime-Only-500px,TopLeft,0,0_.jpg'}], u'hasTrailerEncode': False, u'hasEncode': False}], u'customerReviewCollection': {u'customerReviews': [], u'customerReviewSummary': {u'totalReviewCount': 0, u'threeStarReviewCount': 0, u'averageOverallRating': 0.0, u'twoStarReviewCount': 0, u'fiveStarReviewCount': 0, u'oneStarReviewCount': 0, u'fourStarReviewCount': 0}}, u'runtime': {u'valueMillis': 2820000, u'valueFormatted': u'47m'}, u'contractID': u'UXSG4'}

我正在嘗試通過以下方式獲得所有asin ：

possible_episode_ids = []
for item in t['formats']:
    for i in item['offers']:
        possible_episode_ids.append(i['asin']) 

>>> possible_episode_ids
[u'B0043YVHMY', u'B00ILZOQWE', u'B00QVECS4U', u'B0043YVHMY', u'B00ILZOR9Q', u'B00QVFSN0W']

如何使用列表理解功能？

Answer 1

只需復制現有行：

possible_episode_ids = [
    i['asin']
    for item in t['formats']
    for i in item['offers']
]

Answer 2

嘗試這個：

possible_episode_ids=[offer['asin']  for fmt in t['formats'] for offer in fmt['offers']]

Answer 3

possible_episode_ids = [j['asin'] for i in t['formats'] for j in i['offers']]