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Thread: Syntax Question...

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    Default Syntax Question...

    Good evening all,

    I hope everyone is well. I'm OK, but I need a little help trying to figure out how to properly code a particular statement, namely this:

             if (input.indexOf("a").equals("a"))

    Obviously that is not correct, .equals is not going to work here, but I also know that I cannot use the == operator either. I can't say:
    if(input.indexOf("a") == "a")
    I'm working on an Atbash cipher, i.e. I need to find a character in a string and swap it with another. In this case, "a" will become "x" and so on.

    If anyone can help, I would really appreciate it. Thanks guys.


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    Default Re: Syntax Question...

    Hi,

    indexOf() method returns only a index number it not return letter or string. So dont compare using equals() method.

    Generally if you want to compare number means you can use == operator. If you want to compare string means you can use equals() method

    k. If you want to swap letter means you can use replace(oldChar, newChar)

    Happy to help

    Thanks,

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    Default Re: Syntax Question...

    Ahhhhhhh. Well that would make things much simpler indeed. Mucho appreciado Ganeprog. And thanks for explaining things as well.

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    Default Re: Syntax Question...

    Thanks, Happy coding

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    Default Re: Syntax Question...


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    Default Re: Syntax Question...

    I'm going to say what Ganeprog said differently:

    The equals() method is used to determine whether one object is equivalent to another object, as in:

    this.equals( that );

    where 'this' and 'that' are two objects. equals() will return true if 'this' and 'that' are of the same type and have the same attributes, false otherwise. The Object class includes an equals() method, and since all Java classes descend from Object, all Java classes have an equals() method. However, the equals() method provided by the Object class may not give the desired results for every Java class, so it is the programmer's responsibility to override Object.equals() as needed. Writing a good and proper equals() method is a good study topic if you get bored and need something to do.

    Primitives (int, double, char, etc.) are not objects so cannot use a method following the dot, '.', operator like .equals() as objects can. We use and treat Strings as primitives so often that we forget they are objects, and we're surprised and disappointed when a String object rudely reminds us of that fact by not "acting" as we'd hoped it would.

    Keep coding.

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