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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.
def letterCheck(aString): if len(aString) > 0: if re.match("[a-zA-Z]", aString) != None: return "" return "Enter letters only" 
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\w -- (lowercase w) matches a "word" character: a letter or digit or underbar [a-zA-Z0-9_]. Note that although "word" is the mnemonic for this, it only matches a single word char, not a whole word. \W (upper case W) matches any non-word character. \b -- boundary between word and non-word.
match() function of re in Python will search the regular expression pattern and return the first occurrence. The Python RegEx Match method checks for a match only at the beginning of the string. So, if a match is found in the first line, it returns the match object.
Both return the first match of a substring found in the string, but re. match() searches only from the beginning of the string and return match object if found. But if a match of substring is found somewhere in the middle of the string, it returns none.
Anchor it to the start and end, and match one or more characters:
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.
You'd be better off just using str.isalpha() instead though. No need to reach for the hefty regular expression hammer here:
>>> 'foobar'.isalpha() True >>> 'foobar42'.isalpha() False >>> ''.isalpha() False If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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