Python-如何使用 re 匹配整个字符串
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Python- how do I use re to match a whole string
提问by Thomas
I am validating the text input by a user so that it will only accept letters but not numbers. so far my code works fine when I type in a number (e.g. 56), it warns me that I should only type letters and when I type in letters it doesn't return anything (like it should do). My problem is that it accepts it when I start by typing letters followed by numbers e.g. (s45). what it does is accept the first letter but not the whole string. I need it to accept the whole string.
我正在验证用户输入的文本，以便它只接受字母而不接受数字。到目前为止，当我输入一个数字（例如 56）时，我的代码工作正常，它警告我应该只输入字母，而当我输入字母时，它不会返回任何内容（就像它应该做的那样）。我的问题是当我开始输入字母后跟数字时它会接受它，例如（s45）。它的作用是接受第一个字母而不是整个字符串。我需要它来接受整个字符串。
def letterCheck(aString):
if len(aString) > 0:
if re.match("[a-zA-Z]", aString) != None:
return ""
return "Enter letters only"
采纳答案by Martijn Pieters
Anchor it to the start and end, and match one or morecharacters:
将其锚定到开头和结尾，并匹配一个或多个字符：
if re.match("^[a-zA-Z]+$", aString):
Here ^anchors to the start of the string, $to the end, and +makes sure you match 1 or more characters.
此处^锚定到字符串的开头和$结尾，并+确保匹配 1 个或多个字符。
You'd be better off just using str.isalpha()instead though. No need to reach for the hefty regular expression hammer here:
不过，您最好只使用str.isalpha()它。无需在这里使用庞大的正则表达式锤子：
>>> 'foobar'.isalpha()
True
>>> 'foobar42'.isalpha()
False
>>> ''.isalpha()
False
回答by Aprillion
use boundaries in your regex + raw string to encode the regex, like this:
在正则表达式 + 原始字符串中使用边界对正则表达式进行编码，如下所示：
r"^[a-zA-Z]+$"
回答by sizzzzlerz
You might consider using isalpha() on the string. It returns true if the string contains nothing but alphabetic characters, false otherwise.
您可以考虑在字符串上使用 isalpha() 。如果字符串只包含字母字符，则返回 true，否则返回 false。
if aString.isalpha():
do something
else:
handle input error
回答by Louis
if you look for pretty pythonic writings, go for isalpha and isdecimal :
如果您寻找漂亮的 Pythonic 作品，请选择 isalpha 和 isdecimal ：
str = u"23443434";
print str.isdecimal();
