Split string on uppercase only if next character is lowercase

Question

I have found numerous examples on how to split a string on uppercase, example:

"MyNameIsRob" returns "My Name Is Rob"

My scenario is a bit differnet through....

I would like to accomplish the following:

"MyFavouriteChocIsDARKChocalate" should return "My Favourite Choc Is DARK Chocalate"

The only way I can think of doing this, is to only split the string on upperacase if the next character is lowercase.

Any idea on how to achieve this?

It would probably be easier to modify your existing solution to follow new requirement. Could you post your existing code? — MarcinJuraszek, Mar 18 '14 at 17:31
Check out this answer to a similar question: http://stackoverflow.com/a/3216204/34720 - Based on a quick test it appears to do what you're looking for. — MrDustpan, Mar 18 '14 at 17:32
That would be the easiest and most straightforward way to do it. — ElGavilan, Mar 18 '14 at 17:32

score 6 · Accepted Answer · answered Mar 18 '14 at 17:40

You can do a Regex replace with lookahead and lookbehind to find uppercase with a lowercase before or after it...

var input = "MyFavouriteChocIsDARKChocalate";
var output = Regex.Replace(input, "(((?<!^)[A-Z](?=[a-z]))|((?<=[a-z])[A-Z]))", " $1");
Console.WriteLine(output);

http://dotnetfiddle.net/cIM6QG

Brocco · Answer 2 · 2015-08-18T01:04:23.153

Without regex, you could use this:

public static string SplitOnCaps(string s)

http://dotnetfiddle.net/qQIIgX :

using System;
using System.Collections.Generic;
using System.Text;

public class Program
{
    public static void Main()
    {
        /*"MyFavouriteChocIsDARKChocalate" should return "My Favourite Choc Is DARK Chocalate"*/
        var input = "MyFavouriteChocIsDARKChocalate";
        var split = SplitOnCaps(input);
        Console.WriteLine(input + " --> " + split);
        var match = "My Favourite Choc Is DARK Chocalate";

        Console.WriteLine(split == match ? "Match" : "No Match");       
    }

    public static string SplitOnCaps(string s)
    {
        var splits = new List<int>();

        var chars = s.ToCharArray();

        for(var i=1; i<chars.Length-1; i++)
        {
            if (IsCapital(chars[i]) && !IsCapital(chars[i+1]) ||
               IsCapital(chars[i]) && !IsCapital(chars[i-1]))
            {
                splits.Add(i);
            }
        }

        var sb = new StringBuilder();

        var lastSplit = 0;
        foreach(var split in splits)
        {
            sb.Append(s.Substring(lastSplit, split - lastSplit) + " ");
            lastSplit = split;
        }
        sb.Append(s.Substring(lastSplit));

        return sb.ToString();
    }
    public static bool IsCapital(char c)
    {
        var i = (int)c;
        return i>=65 && i<=90;
    }
}

Note: I am not fluent in Regex

Dmitry · Answer 3 · 2014-03-18T18:04:19.513

1

Maybe classic approach will fit your need:

private static string[] SplitSpecial(string s)
{
    List<string> tmp = new List<string>();
    int lastindex = 0;
    for (int i = 1; i < s.Length; i++)
        if (Char.IsUpper(s[i]) && (Char.IsLower(s[i - 1]) || (i < s.Length - 1 && Char.IsLower(s[i + 1]))))
        {
            if (i > lastindex)
                tmp.Add(s.Substring(lastindex, i - lastindex));
            lastindex = i;
        }
    tmp.Add(s.Substring(lastindex, s.Length - lastindex));
    return tmp.ToArray();
}

To make a single string you can String.Join the resulting array:

string singleStr = String.Join(" ", SplitSpecial("MyFavouriteChocIsDARKChocalate"));

edited Mar 18 '14 at 18:04

answered Mar 18 '14 at 17:41

Dmitry

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would this not be quicker than the regex examples provided? I know regex can be slow sometimes – stoic Mar 18 '14 at 17:44
According to the test (run both methods 1mln times), my sample is 10 times faster. – Dmitry Mar 18 '14 at 17:53

score 1 · Answer 4 · answered Mar 18 '14 at 17:48

Classic approach + using stringBuilder (more efficient if you work with long strings) :

    string str = "MyFavouriteChocIsDARKChocalate";
    System.Text.StringBuilder output = new System.Text.StringBuilder(str.Substring(0,1));

    for (int i = 1; i < str.Length; i++)
    {
        if (Char.IsUpper(str[i]) && (!char.IsUpper(str[i-1]) || (i+1 < str.Length && char.IsLower(str[i+1]))))
        {
            output.Append(" " + str[i]);
        }
        else
        {
            output.Append(str[i]);
        }
    }
    string result = output.ToString();

Split string on uppercase only if next character is lowercase

4 Answers4