how to check first character of a string if a lett

问题:

i want to take a string and check the first character for being a letter, upper or lower doesn't matter, but it shouldn't be special, a space, a line break, anything

thanks in advance, hope this is easy for someone

回答1:

Try the following

string str = ...;
bool isLetter = !String.IsNullOrEmpty(str) && Char.IsLetter(str[0]);

回答2:

Try the following

bool isValid = char.IsLetter(name.FirstOrDefault());

回答3:

return (myString[0] >= 'A' && myString[0] <= 'Z') || (myString[0] >= 'a' && myString[0] <= 'z')

回答4:

You should look up the ASCII table, a table which systematically maps characters to integer values. All lower-case characters are sequential (97-122), as are all upper-case characters (65-90). Knowing this, you do not even have to cast to the int values, just check if the first char of the string is within one of those two ranges (inclusive).