find index of list with params c#

Question

I'm basically trying to convert this:

private int FindIndexOf(string valueOne, string valueTwo, List<string> list)
{
    return list.FindIndex(s =>
        s.ToLower().Contains(valueOne.ToLower()) &&
        s.ToLower().Contains(valueTwo.ToLower())
        );
}

to make use of params like this:

private int FindIndexOf(List<string> list, params string[] args)
{
    string pattern = String.Format("([{0}]+)", String.Join("]+[", args));
    Regex regEx = new Regex(pattern, RegexOptions.IgnoreCase);
    return list.FindIndex(s => regEx.IsMatch(s.ToLower()));
}

I'm not very good with RegEx and I can't think of a way to implement this in linq. Any suggestions?

score 3 · Accepted Answer · edited May 23 '17 at 10:25

3

You don't need regex and you don't need ToLower:

private int FindIndexOf(List<string> list, params string[] args)
{
    return list
       .FindIndex(s => args
           .All(str => s.IndexOf(str, StringComparison.OrdinalIgnoreCase) >= 0));
}

Why ToLower can be incorrect: https://stackoverflow.com/a/234751/284240

edited May 23 '17 at 10:25

Community

1
1

answered Dec 06 '13 at 23:40

Tim Schmelter

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Ah that makes sense. Thank you for the link on ToLower. I'll definitely stop using that in my code! – DobleA Dec 07 '13 at 00:11

score 1 · Answer 2 · answered Dec 06 '13 at 23:39

1

Use All instead:

var argsLower = args.Select(q=> q.ToLower());
list.FindIndex(c => argsLower.All(x => c == x));

answered Dec 06 '13 at 23:39

Jens Kloster

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score 0 · Answer 3 · answered Dec 06 '13 at 23:53

A regex-based solution, for the record:

private int FindIndexOf(List<string> list, params string[] args)
{
    string pattern = args.Aggregate(new StringBuilder(), 
        (sb, a) => sb.Append("(?=.*").Append(Regex.Escape(a)).Append(")")
    ).ToString();
    Regex regEx = new Regex(pattern, RegexOptions.IgnoreCase);
    return list.FindIndex(s => regEx.IsMatch(s));
}

find index of list with params c#

3 Answers3