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Sean Francis N. Ballais
Sean Francis N. Ballais

Posted on

How can I improve this while loop code snippet?

So, I have this code snippet.

while (!Character.isWhitespace(this.source.charAt(this.currentCharIndex))) {
    char c = this.source.charAt(this.currentCharIndex);
    // ...
}
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What it does is just basically loops through a string until it hits a white space character.

However, I find the code a bit messy. How can I improve it?

I can try this code snippet instead.

char c = this.source.charAt(this.currentCharIndex);
while (!Character.isWhitespace(c)) {
    c = this.source.charAt(this.currentCharIndex);
}
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It looks cleaner but this.source.charAt(this.currentCharIndex) seems redundant (the same as the previous snippet) so I need your opinion on how you would tackle this problem.

Thanks! :D

Top comments (9)

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fabulousyap profile image
fabulous.yap

maybe...

        char c;
        while (!Character.isWhitespace(c=source.charAt(currentCharIndex++))) {
            //do code magic here...
        }

or

        char c;
        while (!Character.isWhitespace(c=source.charAt(currentCharIndex))) {
            currentCharIndex++;
            //more code magic happen after this...
        }

but I know nothing of what happen next tho... I assume currentCharIndex will be increment somewhere in the loop...

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kspeakman profile image
Kasey Speakman • Edited on

(I don't use Java, but) I'd probably use the Java Streams API.

Optional<int> whitespaceIndex =
    IntStream.range(0, this.source.length())
        .filter(i -> Character.isWhiteSpace(this.source.charAt(i)))
        .findFirst();
Optional<char> whitespaceChar = whitespaceIndex.map(i -> this.source.charAt(i));

Using Optional makes it obvious you have to handle when whitespace is not found.

Note: not guaranteed to compile.

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fnh profile image
Fabian Holzer • Edited on

Well, you give very little context about your intentions.

If it is safe to assume that currentCharIndex is within the correct bounds, you might get rid of the assignment outside of the loop by using do { } while.

Or, you get rid of the imperative style by using Streams (you get an IntStream from a String using the chars() method in Java 8).

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seanballais profile image
Sean Francis N. Ballais Author

Interesting. I'm actually creating a tokenizer for a programming language we came up as part of our course curriculum.

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mortoray profile image
edA‑qa mort‑ora‑y

Use a find_first function, writing your own if it doesn't exist.

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alainvanhout profile image
Alain Van Hout

If you simply want the first instance of a certain character, and the context is not more complex, and it doesn't require hyper-optimisation, then just go with source.indexOf(" ")

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kingo profile image
kingoftwo

char c = this.source.charAt(this.currentCharIndex);
while (!Character.isWhitespace(c)) {
char d = c;
}
}

Gave up on markdown..

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seanballais profile image
Sean Francis N. Ballais Author

It's Java (though I initially thought there was enough clues that it was Java, my bad). The code snippet is actually inside a class.

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