2012年12月18日 · Just a quick note to all those "num = letter - 'A'" crowd. The C99 standard requires that the digit characters ('0'-'9') are consecutive but not the letter characters: "In both the source and execution basic character sets, the value of each character after 0 in the above list of decimal digits shall be one greater than the value of the previous.".

Use string.ascii_letters instead of string.letters if you don't use re.LOCALE flag for regexps (otherwise you might get false positive results in check_trans(). string.maketrans() will not work for unicode strings. –

Im not sure how I can achieve this match expression. Currently I am using, ([A-Za-z0-9-]+) ...which matches letters and numbers. I would also like to match on dashes and underscores in the same

2012年8月5日 · I'm quite new to Java so I am wondering how do you convert a letter in a string to a number e.g. hello world would output as 8 5 12 12 15 23 15 18 12 4. so a=1, b=2, z=26 etc.

2015年8月1日 · The ^ and $ match the start and end of the string, so the whole string will be tested for the conditions. The [a-z0-9] makes it match only letters and numbers. The + makes it match one or more character. And the "i" at the end, as you know, makes it case insensitive.

I have to write a program that checks if a user's variable name is valid. These are the rules I am checking for: Only letters, numbers, and the underscore character are allowed. The first character cannot be a number. I am not sure what I am doing wrong. Every time I run the program, it tells me that it's a valid variable, even for invalid inputs.

[a-zA-Z0-9]+ One or more letters or numbers. The extension must be at least one character long and must contain only letters and numbers. This is typical, but if you wanted allow underscores, that could be addressed as well. You could also supply a length range {2,3} instead of the one or more + matcher, if that were more appropriate.

2022年10月17日 · "I would like to have a regular expression that checks if a string contains only upper and lowercase letters, numbers, and underscores" doesn't limit it to Latin letters. "The following regex matches alphanumeric characters and underscore" doesn't limit it to Latin letters. "^[a-zA-Z0-9_]+$" fails. –

2012年8月12日 · The only precedent I am aware of for such a set is the Canada Postal code system that removes the letters D, F, I, O, Q, and U, and that subset was created to aid the postal system's OCR process. My initial thought is to use only capital letters and numbers as follows:

2018年4月10日 · I am trying to convert a string of letters to a set of 2 digit numbers where a = 10, b = 11, ..., Y = 34, Z = 35 so that (for example) "abc def" goes to "101112131415". How would I go about doing this? Any help would really be appreciated. Also, I don't mind whether capitalization results in the same number or a different number.