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Thread: How to find the first character which occurs only once in string?

  1. #1
    Junior Member
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    Arrow How to find the first character which occurs only once in string?

    I have a string "refer reference-book" and I want to find the first character which occurs only once, in this string I have 2 characters which occurs only once which is a space " " and a hyphen "-" but the first character is space " " so I want to return that from a method.

    How to do this?

  2. #2
    Super Moderator Norm's Avatar
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    May 2010
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    Default Re: How to find the first character which occurs only once in string?

    Please define what you mean by "first character".

    The count of the occurrences of characters could be done with a Map<char, position>. If item already in Map, then it occurs more than once.
    Or by using an int array with the char value used as the index into the array: count['a']++ to count the letter 'a'. Then search the array for counts of 1.

    --- Update ---

    Also posted here: https://coderanch.com/t/731067/java/...-occurs-string
    If you don't understand my answer, don't ignore it, ask a question.

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