我目前正在學(xué)習(xí)字符串方法。但是，我遇到了這個(gè)問題，出現(xiàn)了 ValueError。我有一個(gè)名為列表的列表，result_list其中行的第一個(gè)索引是日期/時(shí)間戳，第二個(gè)索引是評(píng)論數(shù)。我被要求執(zhí)行以下操作：從日期中提取小時(shí)，這是該行的第一個(gè)元素。使用該datetime.strptime()方法解析日期并創(chuàng)建日期時(shí)間對(duì)象。from datetime import datetime# here is your list of valuesresult_list = ['8/16/2016 9:55', '6.0', '11/22/2015 13:43', '29.0']# set the formatdate_format = '%m/%d/%Y %H:%M'for row in result_list: time = row[0] time_dt = datetime.strptime(time, date_format)錯(cuò)誤---------------------------------------------------------------------------ValueError Traceback (most recent call last)<ipython-input-6-ecf5afb3f99e> in <module> 9 for row in result_list: 10 time = row[0]---> 11 time_dt = datetime.strptime(time, date_format)e:\Anaconda3\lib\_strptime.py in _strptime_datetime(cls, data_string, format) 566 """Return a class cls instance based on the input string and the 567 format string."""--> 568 tt, fraction, gmtoff_fraction = _strptime(data_string, format) 569 tzname, gmtoff = tt[-2:] 570 args = tt[:6] + (fraction,)e:\Anaconda3\lib\_strptime.py in _strptime(data_string, format) 347 found = format_regex.match(data_string) 348 if not found:--> 349 raise ValueError("time data %r does not match format %r" % 350 (data_string, format)) 351 if len(data_string) != found.end():ValueError: time data '8' does not match format '%m/%d/%Y %H:%M'我假設(shè)我收到錯(cuò)誤是由于datetime.strptime()構(gòu)造函數(shù)期望值為 08 而不是 8。但是，我不確定從哪里開始解決此問題。
1 回答
慕娘9325324
TA貢獻(xiàn)1783條經(jīng)驗(yàn) 獲得超4個(gè)贊
result_list是一個(gè)平面列表，沒有組，索引 0 處的值的 ,row[0]也是如此。8
將日期值正確轉(zhuǎn)換為日期時(shí)間后，請(qǐng)使用各種方法（例如 ）.hour來提取所需的值。
一種選擇是使用列表理解對(duì)日期和相關(guān)評(píng)論計(jì)數(shù)進(jìn)行分組。
from datetime import datetime
# here is your list of values
result_list = ['8/16/2016 9:55', '6.0', '11/22/2015 13:43', '29.0']
# set the format
date_format = '%m/%d/%Y %H:%M'
# group each date and count together
rl_updated1 = [result_list[k:k+2] for k in range(0, len(result_list), 2)]
print(rl_updated1)
[out]:
[['8/16/2016 9:55', '6.0'], ['11/22/2015 13:43', '29.0']]
# convert to a datetime format in a list comprehension
rl_updated2 = [[datetime.strptime(v[0], date_format), v[1]] for v in rl_updated1]
print(rl_updated2)
[out]:
[[datetime.datetime(2016, 8, 16, 9, 55), '6.0'],
[datetime.datetime(2015, 11, 22, 13, 43), '29.0']]
# alternatively, iterate through rl_updated1, before converting to a date format
for group in rl_updated1:
dt = group[0]
dt = datetime.striptime(dt, date_format)
保持平面列表，并從索引中選擇日期，其中i % 2 == 0
for i, v in enumerate(result_list):
if i%2 == 0:
time_dt = datetime.strptime(v, date_format)
print(time_dt)
else:
comment = v
print(v)
[out]:
2016-08-16 09:55:00
6.0
2015-11-22 13:43:00
29.0
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