import re
匹配字串
# pattern = re.compile(r'hello')
# match = pattern.search('ni hello cxy61!') #全字元匹配字串 .search()
# search = pattern.match('ai hello') #只在開頭匹配字串  .match()
# if match:
#     print(match.group())
# else:
#     print('no match.')
#
# if search:
#     print(search.group())
# else:
#     print('no search')
 


替換
time = '2017-10-01'
pattern = re.compile(r'\D')  #匹配非數字的字元
sub = pattern.sub('/',time) #替換非數字的字元
print(sub)
print(re.sub(r'\D','/',time)) #也可以這樣寫，re.sub(表示式,替換字元,內容)
#\D非數字的,'/'替換字元，time目標；把time裡面非數字的都替換為/