How to find the index of the first char in a string that is not in the list
I know I can iterate over a string or build a regex or invert the set (ASCII isn't that big) and look for the first instance of that, but Yuck.
What I'm looking for is a good liner.
fewer functions are better, LINQ is missing (for me don't ask, it's a long story)
Solution i am going with (unless i see anything better)
static int FirstNotMeta(int i, string str)
{
for(; i < str.Length; i++)
switch(str[i])
{
case '\\':
case '/':
case '.':
continue;
default:
return i;
}
return -1;
}
OK, I cheated, I know in advance what char is about.
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If you don't have access to LINQ, I think you just need to write a static method with a loop (which is probably more efficient than LINQ). Remember that the compiler will create small methods someday.
The simplest non-LINQ I can think of is below. I recommend adding curly braces to keep the scope transparent:
public static char? GetFirstChar(string str, char[] list)
{
foreach (char c in str) if (!list.Contains(c)) return c;
return null;
}
With C # 3.0 and LINQ:
char[] list = { 'A', 'B' };
string str = "AABAGAF";
char first = str.ToArray().Where(c => !list.Contains(c)).FirstOrDefault();
In this case, if there is no character without a list, it will first be 0x0000 (or null character). You can do it:
char? first = str.ToArray().Cast<char?>().Where(
c => !list.Contains(c.Value)).FirstOrDefault();
Then it will be null first if there is no match. It can also be written as:
var query = from char c in str
where !list.Contains(c)
select (char?)c;
char? first = query.FirstOrDefault();
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Will this C / C ++ example work for you:
char *strToSearch = "This is the one liner you want"
char *skipChars = "Tthise";
size_f numToSkip = strcspn(strToSearch, skipChars);
The function strcspn()
scans a string for complement to the specified set. It returns the number of leading characters that do not include a character in the set.
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