list index out of range  列表越界

Traceback (most recent call last):
  File "G:/workSpace/Python/TB_Crawler/Crawler_train.py", line 71, in <module>
    print(getCommentsList(ItemURL2))
  File "G:/workSpace/Python/TB_Crawler/Crawler_train.py", line 46, in getCommentsList
    comment = getComment(newURL, i)['content']
  File "G:/workSpace/Python/TB_Crawler/Crawler_train.py", line 27, in getComment
    comment = jd['comments'][num]

IndexError: list index out of range

提示錯誤在getComment方法的comment = jd['comments'][num]中

因為淘寶評論每一頁最多20條評論，所以爬取評論時對每頁的20條評論進行遍歷。當某頁評論小於20條時，num仍然是從0到20遍歷，所以就會出現列表越界的問題。

解決辦法：當遍歷到最後一條評論時break，跳出迴圈。

# 獲取商品id
def getItemID(url):
    m = re.search('id=(.+)', url)
    itemID = m.group(1)[0:12]
    return itemID

# 獲取評論數
 
def getCommentCount(url):
    # countURL = 'https://rate.taobao.com/detailCount.do?_ksTS=1516697185953_173&callback=jsonp174&itemId={}'
countURL = 'https://rate.taobao.com/feedRateList.htm?auctionNumId={}&userNumId=352740130&currentPageNum=1'
res = requests.get(countURL.format(getItemID(url)))
    # jd = json.loads(res.text.strip('jsonp174()'))
 
jd = json.loads(res.text.strip().strip('()'))
    return jd['total']

# 獲取每條評論及時間
def getComment(url, num):
    result = {}
    res = requests.get(url)
    jd = json.loads(res.text.strip().strip('()'))
    comment = jd['comments'][num]
    # print(comment)
    # result['date'] = comment['date']
result['content'] = comment['content']
    return result

# 將評論填入列表
def getCommentsList(url):
    commentList = []
    page = 1
maxCount = getCommentCount(url)
    count = 0
# num = 0
while count < maxCount:
        commentURL = 'https://rate.taobao.com/feedRateList.htm?auctionNumId={}&userNumId=352740130&currentPageNum=1'
newURL = commentURL.format(getItemID(url))[:-1] + str(page)
        page = page + 1
for i in range(0, 20):
            comment = getComment(newURL, i)['content']
            if comment != '15天內買家未作出評價' and comment != '評價方未及時做出評價,系統預設好評!' and comment != '此使用者沒有填寫評價。':
                commentList.append(getComment(newURL, i))
                # num = num+1
                # print(comment, num)
            # 獲取追加評論
            # if comment['append'] is not None:
                # commentList.append(comment['append']['content'])
count = count + 1
if count >= maxCount: break
    return commentList