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
+16
A:
Try the following
string str = ...;
bool isLetter = !String.IsNullOrEmpty(str) && Char.IsLetter(str[0]);
JaredPar
2010-08-24 19:43:31
Slightly shorter: `Char.IsLetter(str.FirstOrDefault())`
driis
2010-08-24 19:45:09
@driis that works but it adds several unnecessary allocations to what should be an allocation free check
JaredPar
2010-08-24 19:49:23
thank you everyone for your help, i wasn't sure who to award since you all helped, i just went with the highest number already figured first wins? thanks everyone though.
korben
2010-08-24 19:57:11
A:
return (myString[0] >= 'A' && myString[0] <= 'Z') || (myString[0] >= 'a' && myString[0] <= 'z')
Mark Mullin
2010-08-24 19:44:19
The days of ASCII are gone. Now all the cool kids are using Unicode! http://www.joelonsoftware.com/articles/Unicode.html
Martinho Fernandes
2010-08-24 19:48:33
This will throw an exception if the string is empty. You need to check `!String.IsNullOrEmpty(myString)` first.
Brian
2010-08-24 20:32:02
A:
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).
@maxstar: Knowing that ASCII uses sequential values for `A-Z` and `a`-`z`, I would prefer Mark's solution over this, as his solution avoids using magic numbers. You could also adjust your solution to define constants somewhere to hold 97/122/65/90, but that is adding unneeded constants, so I still prefer Mark's solution. Of course, calling `Char.IsLetter` as suggested by JaredPar is even better.
Brian
2010-08-24 20:34:53
I completely agree that using Char.IsLetter may be better. I am merely suggesting that korben look up the ASCII table to know that characters aren't just randomly floating in cyber space, but are systematically structured and mapped to numbers. I believe knowing this is more important and beneficial than simply getting an answer to the posted question, because this provides underlying understanding. And by the way, I meant exactly what Mark wrote: when I said "within one of those two ranges" I meant ranges of chars, not ints. Sorry for the misunderstanding.
2010-08-24 21:47:02