python - RE 的 HTML ID 值验证

Question

问题陈述:

ID value must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").

我是通过正则表达式完成的。

代码:

>>> import re
>>> id_value1 =  "custom-title1"
>>> id_value2 =  "1-custom-title"
>>> pattern = "[A-Za-z][\-A-Za-z0-9_:\.]*"

有效ID值代码

>>> flag= False
>>> try:
...     if re.finadll(pattern, id_value1)[0]==id_value1:
...         flag=True
... except:
...     pass
... 
>>> print flag
False

无效 ID 值代码:

>>> flag = False
>>> try:
...     if re.findall(pattern, id_value2)[0]==id_value2:
...         flag=True
... except IndexError:
...     pass
... 
>>> print flag
False

IndexError 代码

>>> try:
...     if re.findall(pattern, "")[0]=="":
...         print "In "
... except IndexError:
...    print "Exception Index Error"
... 
Exception Index Error
>>> 

我将在一个函数中移动上面的代码。此函数将调用超过 1000 次。那么有人可以优化上面的代码吗？

Answer 1

你应该匹配字符串的结尾，编译你的模式并使用 re.match() 而不是 re.findall()

import re
id_value1 =  "custom-title1"
id_value2 =  "1-custom-title"

pattern = "[A-Za-z][\-A-Za-z0-9_:\.]*$"
compiled = re.compile(pattern)

def validate(id):
    return bool(compiled.match(id))

print validate(id_value1)
print validate(id_value2)