If statement for even/odd numbers

[Jad Tamimi]

Hello, Im working with the following code:

forvalues x = 1/4 {

if `x' == 1 | `x'==3 {
    local test "hello"
}

if `x' == 2 | `x'==4 {
    local test "bye"
}


display "`test'"


}

You see how I have to list out the even numbers and odd numbers to tell stata how to act, I want to simply do something like this ( if `x' == even ) or ( if `x'==odd). How can I implement something like this?
Thanks,
Jad

[Daniel Schaefer]

You need the mod() function. Mod checks to see what the remainder is when the first number is divided by the second number. If you divide by 2 and the remainder is 1, the number is odd. (Remember, 1 is equivalent to true.) If the remainder is 0, the number is even, (and 0 corresponds to false).

forvalues x = 1/10 {
    if mod(`x', 2) {
        display "odd"
    }

    else {
        display "even"
    }
}

[Nick Cox]

forvalues x = 1/4 {
    
di cond(mod(`x', 2), "hello", "bye")

}

On what you can do with mod(,) see e.g.

SJ-7-1 pr0031 . Stata tip 43: Remainders, selections, sequences, extractions
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox
Q1/07 SJ 7(1):143--145 (no commands)
tip for uses of the modulus


SJ-11-3 dm0058 . . . . . . . . Speaking Stata: Fun and fluency with functions
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox
Q3/11 SJ 11(3):460--471 (no commands)
a tour of easily missed or underestimated Stata functions

[Scott Merryman]

forvalues x = 1/4 {
    if mod(`x', 2) == 1 {
        local test "odd"
    }

    if mod(`x', 2) == 0 {
        local test "even"
    }
    display "`test'"
}

[Nick Cox]

What we tell you three times is true. See for example in https://www.statalist.org/forums/for...ete-forum-post that statement being exemplified, explained and endorsed.

[Jad Tamimi]

Thanks everyone!