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Posted 9 Feb 2011

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How to Toggle String Case in .NET

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4.41/5 (9 votes)
14 Feb 2011CPOL
Shows how to toggle the contents of a string from upper case to lower, or vice versa
The following snippet shows how to toggle string casing in .NET:

public string ToggleCase(string input)
    string result = string.Empty;
    char[] inputArray = input.ToCharArray();

    foreach (char c in inputArray)
        if (char.IsLower(c))
            result += c.ToString().ToUpper();
        else if (char.IsUpper(c))
            result += c.ToString().ToLower();
            result += c.ToString();

    return result;

This code snippet could be simplified as follows:
public string ToggleCase(string input)
    string result = string.Empty;
    char[] inputArray = input.ToCharArray();
    foreach (char c in inputArray)
        if (char.IsLower(c))
            result += Char.ToUpper(c);
            result += Char.ToLower(c);
    return result;

But still performance of Alternate 1 and Alternate 2 is 2...3 times better than of this one: see the online comparative test at:[^]

Alex Bell


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Manas Bhardwaj
Netherlands Netherlands

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Comments and Discussions

GeneralRe: 1. Thanks for your note: I typically use "Add comment" becau... Pin
DrABELL23-Feb-11 15:23
MemberDrABELL23-Feb-11 15:23 
GeneralReason for my vote of 1 result = instead of StringBuilder Pin
Selvin9-Dec-11 5:57
MemberSelvin9-Dec-11 5:57 
GeneralAre you going to add the other alternatives to your webinfoc... Pin
SimmoTech23-Mar-11 23:06
MemberSimmoTech23-Mar-11 23:06 
GeneralGot the highest number of alternatives.. I have not seen cod... Pin
Pravin Patil, Mumbai8-Mar-11 22:47
MemberPravin Patil, Mumbai8-Mar-11 22:47 
GeneralTwo fastest Toggle Case Algorithms (Ayoola-Bell and Bell-Ned... Pin
DrABELL23-Feb-11 9:01
MemberDrABELL23-Feb-11 9:01 
GeneralRe: I know, I was just saying that those faster solutions do not... Pin
AspDotNetDev23-Feb-11 12:51
protectorAspDotNetDev23-Feb-11 12:51 
GeneralReason for my vote of 5 I am giving my vote of 5 because the... Pin
DrABELL14-Feb-11 17:29
MemberDrABELL14-Feb-11 17:29 
GeneralRe: Actually, the performance can be increased by a multiple of ... Pin
AspDotNetDev23-Feb-11 7:57
protectorAspDotNetDev23-Feb-11 7:57 
General[edit] made variable names more C#-ish. (no vote from me, b... Pin
Indivara14-Feb-11 14:08
professionalIndivara14-Feb-11 14:08 
GeneralReason for my vote of 5 the way to toggle the string is opti... Pin
shadi_abushaar13-Feb-11 1:54
Membershadi_abushaar13-Feb-11 1:54 
GeneralRe: you have a strange idea of "optimal"... Pin
Seishin#9-Dec-11 0:16
MemberSeishin#9-Dec-11 0:16 
GeneralReason for my vote of 3 Neat idea, poorly implemented. Appen... Pin
AspDotNetDev9-Feb-11 14:01
protectorAspDotNetDev9-Feb-11 14:01 
GeneralAs FYI: High Resolution timer added to the test page Pin
DrABELL25-Feb-11 13:40
MemberDrABELL25-Feb-11 13:40 
GeneralSuggestion: to post a summary of this discussion, highlighting the best Algorithms Pin
DrABELL24-Feb-11 14:32
MemberDrABELL24-Feb-11 14:32 
GeneralRe: Suggestion: to post a summary of this discussion, highlighting the best Algorithms Pin
Manas Bhardwaj25-Feb-11 0:52
professionalManas Bhardwaj25-Feb-11 0:52 
QuestionWhy? Pin
Andrew Rissing10-Feb-11 3:57
MemberAndrew Rissing10-Feb-11 3:57 
AnswerRe: Why? Pin
Manas Bhardwaj10-Feb-11 4:12
professionalManas Bhardwaj10-Feb-11 4:12 
GeneralRe: Why? Toggle Case option is included in MS Word, it's a valuable feature Pin
DrABELL24-Feb-11 4:19
MemberDrABELL24-Feb-11 4:19 
AnswerRe: Why? Pin
DrABELL14-Feb-11 16:25
MemberDrABELL14-Feb-11 16:25 
GeneralRe: Why? Pin
Andrew Rissing15-Feb-11 4:27
MemberAndrew Rissing15-Feb-11 4:27 
GeneralRe: Why? Pin
DrABELL15-Feb-11 8:46
MemberDrABELL15-Feb-11 8:46 
GeneralRe: Why? Pin
damnedyankee24-Feb-11 1:27
Memberdamnedyankee24-Feb-11 1:27 
GeneralRe: Why? Pin
DrABELL24-Feb-11 2:22
MemberDrABELL24-Feb-11 2:22 
GeneralRe: Why? Pin
damnedyankee24-Feb-11 3:34
Memberdamnedyankee24-Feb-11 3:34 
GeneralRe: Why? Pin
DrABELL24-Feb-11 4:11
MemberDrABELL24-Feb-11 4:11 

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