一个\d代表一个数字。开头没匹配到,即使字符串其他部分包含需要匹配的内容,.match也会返回none
import re
a = re.match('\d\d','23es12testasdtest')
print(a)
print(a.group())
b = re.match('\d\d\d','23es12testasdtest')
print(b) #要求匹配三个数字,匹配不到返回none
c = re.match('\d','es12testasdtest')
print(c) #起始位置没有匹配成功,一样返回none
输出:
23
None
None
开头没匹配到,即使字符串其他部分包含需要匹配的内容,.match也会返回none
import re
a = re.match('\D','23es12testasdtest')
print(a) #开头为数字所以返回none
b = re.match('\D\D','*es12testasdtest')
print(b) #返回*e
print(b.group())
输出:
None
*e
import re
a=re.match('\s',' 23es 12testasdtest')
print(a)
print(a.group())
print(re.match('\s',' 23es 12testasdtest')) #匹配空格
print(re.match('\s',' 23es 12testasdtest')) #匹配tab
print(re.match('\s','\r23es 12testasdtest')) #匹配\r换行
print(re.match('\s','23es 12testasdtest')) #返回none
输出
None
import re
print(re.match('\S',' 23es 12testasdtest')) #返回none
print(re.match('\S','\r23es 12testasdtest')) #none
print(re.match('\S','23es 12testasdtest'))
a=re.match('\S','23es 12testasdtest')
print(a.group())
输出:
None
None
2
import re
print(re.match('\w','23es 12testasdtest'))
a=re.match('\w','23es 12testasdtest')
print(a.group())
print(re.match('\w\w\w','aA_3es 12testasdtest'))
b=re.match('\w\w\w','aA_3es 12testasdtest')
print(b.group())
print(re.match('\w\w\w','\n12testasdtest')) #返回none
输出:
2
aA_
None
import re
print(re.match('\W','23es 12testasdtest')) #返回none
print(re.match('\W',' 23es 12testasdtest')) #匹配空格
a=re.match('\W',' 23es 12testasdtest')
print(a.group())
输出:
只允许出现[ ]中列举的字符
import re
print(re.match('12[234]','232s12testasdtest')) #因为开头的12没匹配上,所以直接返回none
print(re.match('12[234]','1232s12testasdtest')) #返回123
a=re.match('12[234]','1232s12testasdtest')
b=re.match('12[234]','122454223432s12testasdtest')
c=re.match('12[234]','123562223432s12testasdtest')
d=re.match('12[234]','124223432s12testasdtest')
print(a.group())
print(b.group())
print(c.group())
print(d.group())
输出:
None
123
122
123
124
import re
print(re.match('12[^234]','232s12testasdtest')) #因为开头的12没匹配上,所以直接返回none
print(re.match('12[^234]','1232s12testasdtest')) #返回none
print(re.match('12[^234]','1252s12testasdtest')) #返回125
a=re.match('12[^234]','1252s12testasdtest')
print(a.group())
None
None
125
import re
print(re.match('12[1-3a-c]','1232b12testasdtest'))
print(re.match('12[1-3a-c]','1222b12testasdtest')) #123
print(re.match('12[1-3a-c]','1231b12testasdtest'))
a=re.match('12[1-3a-c]','1232b12testasdtest')
print(re.match('12[1-3a-c]','12b2b12testasdtest')) #12b
print(re.match('12[1-3a-c]','12a2b12testasdtest'))
print(re.match('12[1-3a-c]','12c2b12testasdtest'))
b=re.match('12[1-3a-c]','12b2b12testasdtest')
print(re.match('12[1-3a-c]','12s2b12testasdtest')) #返回none
print(a.group())
print(b.group())
输出:
None
123
12b