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將 none 值替換為同一列表中的值

將 none 值替換為同一列表中的值

ibeautiful 2022-09-20 16:01:39
我是python的新手,我正在為這個例子而苦苦掙扎。我想用列表中的日期替換空元素。例如,每個空元素都被星期一替換到星期二...我使用的是蟒蛇2.7。這是我得到的列表:[u'Monday 30 March', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'Tuesday 31 March', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'Wednesday  1 April', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'', u'']這就是我嘗試過的:for tim in time_d:    if tim =='':        print time_d[0]
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2 回答

?
慕蓋茨4494581

TA貢獻1850條經驗 獲得超11個贊

你在尋找嗎?如下所示:


for i, val in enumerate(time_d):

    if not val:

        time_d[i] = time_d[i-1]


time_d

# ['Monday 30 March', 'Monday 30 March', ... ,'Monday 30 March', 

#  'Tuesday 31 March', 'Tuesday 31 March', ... , 'Tuesday 31 March', 

#  'Wednesday  1 April', 'Wednesday  1 April', ..., 'Wednesday  1 April']


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?
縹緲止盈

TA貢獻2041條經驗 獲得超4個贊

這是一個簡單的解決方案(在Python 3中):


dates = ['Monday 30 March', '', '', '', '', '', '', '', '', '', 'Tuesday 31 March', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', 'Wednesday  1 April', '', '', '', '', '', '', '', '', '', '', '', '', '', '']     

newdates = []

current = ''

for item in dates:

    if not item:

        newdates.append(current)

    else:

        current = item

        newdates.append(current)

print(dates)

print(newdates)

帶輸出:


['Monday 30 March', '', '', '', '', '', '', '', '', '', 'Tuesday 31 March', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', 'Wednesday  1 April', '', '', '', '', '', '', '', '', '', '', '', '', '', '']

['Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Monday 30 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Tuesday 31 March', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April', 'Wednesday  1 April']



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