40 lines
2.5 KiB
Rexx
40 lines
2.5 KiB
Rexx
/*REXX program shows how to assign an empty string, & then check for empty/not-empty str*/
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/*─────────────── 3 simple ways to assign an empty string to a variable.*/
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auk='' /*uses two single quotes (also called apostrophes); easier to peruse. */
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ide="" /*uses two quotes, sometimes called a double quote. */
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doe= /*··· nothing at all (which in this case, a null value is assigned. */
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/*─────────────── assigning multiple null values to vars, 2 methods are:*/
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parse var doe emu pug yak nit moa owl pas jay koi ern ewe fae gar hob
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/*where emu, pug, yak, ··· (and the rest) are all set to a null value.*/
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/*───or─── (with less clutter ─── or more, depending on your perception)*/
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parse value 0 with . ant ape ant imp fly tui paa elo dab cub bat ayu
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/*where the value of zero is skipped, and the rest are set to null,*/
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/*which is the next value AFTER the 0 (zero): nothing (or a null).*/
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/*─────────────── how to check that a string is empty, several methods: */
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if cat=='' then say "the feline is not here."
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if pig=="" then say 'no ham today.'
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if length(gnu)==0 then say "the wildebeest's stomach is empty and hungry."
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if length(ips)=0 then say "checking with == instead of = is faster"
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if length(hub)<1 then method = "this is rather obtuse, don't do as I do ···"
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nit='' /*assign an empty string to a lice egg.*/
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if cow==nit then say 'the cow has no milk today.'
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/*─────────────── how to check that a string isn't empty, several ways: */
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if dog\=='' then say "the dogs are out!"
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/*most REXXes support the ¬ character. */
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if fox¬=='' then say "and the fox is in the henhouse."
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if length(rat)>0 then say "the rat is singing" /*an obscure-ish (or ugly) way to test.*/
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if elk=='' then nop; else say "long way obtuse for an elk to be tested."
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if length(eel)\==0 then fish=eel /*a fast compare (than below), & quick.*/
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if length(cod)\=0 then fish=cod /*a not-as-fast compare. */
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/*────────────────────────── anyway, as they say: "choose your poison." */
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