問題：對字符串中的文本做查找和替換

解決方案：

1、對于簡單模式：str.replace(old, new[, max])

2、復雜模式：使用re模塊中的re.sub(匹配的模式, newstring, oldstring[，替換個數])函數

3、re.subn()可以獲得替換的總次數

# example.py # # Examples of simple regular expression substitutionimport re#simple sample text1='yeah,but no,but yeah,but no,but yeah,but no,but yeah' print (text1.replace('yeah','yeh')) print (text1.replace('no','yes',2)) print ('---------------------------')
# Some sample text text = 'Today is 11/27/2012. PyCon starts 3/13/2013.' datepat = re.compile(r'(\d+)/(\d+)/(\d+)') # (a) Simple substitution \3-表示匹配的模式中第3個模式組 print(datepat.sub(r'\3-\1-\2', text)) #等價于print (re.sub(r'(\d+)/(\d+)/(\d+)',r'\3-\1-\2', text)) print ('*****************************')
# (b) Replacement function 替換回調函數 from calendar import month_abbr def change_date(m):mon_name = month_abbr[int(m.group(1))]return '{} {} {}'.format(m.group(2), mon_name, m.group(3))print(datepat.sub(change_date, text)) print (re.sub(r'(\d+)/(\d+)/(\d+)',change_date, text)) print ('++++++++++++++++++++++++++++++++')

# 通過re.subn()獲取替換的總次數 newtext,n=datepat.subn(r'\3-\1-\2', text)
print (newtext)
print (n) >>> ================================ RESTART ================================ >>> yeh,but no,but yeh,but no,but yeh,but no,but yeh yeah,but yes,but yeah,but yes,but yeah,but no,but yeah --------------------------- Today is 2012-11-27. PyCon starts 2013-3-13. ***************************** Today is 27 Nov 2012. PyCon starts 13 Mar 2013. Today is 27 Nov 2012. PyCon starts 13 Mar 2013. ++++++++++++++++++++++++++++++++ Today is 2012-11-27. PyCon starts 2013-3-13. 2 >>>

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轉載于:https://www.cnblogs.com/apple2016/p/5790780.html

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