How to (selectively) convert array elements to a list of values

Question

Given the array below, how do I convert it to a simple list of values?

<cfdump var="#arguments.ServiceTextArray#">

Array Elements:

   1 3567_no 
   2 3584_yes 
   3 3642_yes 
   4 3643_yes 
   5 3644_no 
   6 3645_no 
   7 3646_no

Specifically, how do I extract values with the "yes" suffix and produce a list like this?

3584,3642,3643

Thanks in advance.

Henry · Answer 1 · 2012-06-19T23:00:45.550

2

var list = "";

for (item in array)
    if (ListLast(item, "_"))
        list = listAppend(list, val(item));

edited Jun 19 '12 at 23:00

answered Jun 18 '12 at 20:36

Henry

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I think they only want "yes" values. – Leigh Jun 18 '12 at 20:40
@Leigh `yes` is a boolean value in CF, so what `listRest(item, "_")` returns will do. – Henry Jun 19 '12 at 05:07
1

@Henry lol, clever, but I think I'd be a bit frustrated if I came across that bit of code while doing maintenance. – Jake Feasel Jun 19 '12 at 05:10
1

@JakeFeasel really? Well, it's like doing `if (x == true)`, kind of unnecessary. However, if the listRest can be some value other than `yes` or `no`, then == "yes" would be a better choice. – Henry Jun 19 '12 at 05:14
1

It is a bit like that, but you have to admit it a bit unusual to expect listRest to just pop out a boolean like that (vs. the not so unusual experience of a simple variable being evaluated as a boolean). – Jake Feasel Jun 19 '12 at 05:18
@JakeFeasel I found many script-based language users use boolean comparison very loosely, to keep things loose. So I took that into my style. :) – Henry Jun 19 '12 at 05:22
@Henry - Neat trick. Though I am with Jake on this one. Given that it is not a simple variable, my preference is usually clarity over clever ;-) But it is a matter of personal style. – Leigh Jun 19 '12 at 12:14
1

There's a big clue that a boolean is coming: *the line starts with **IF*** – Peter Boughton Jun 19 '12 at 22:50
1

(Though I would do `ListLast` instead of `ListRest`, because that's less brittle.) – Peter Boughton Jun 19 '12 at 22:52
Sure you could figure it out, just not as intuitively. Unlike the alternatives, it is less clear what constitutes valid input within the current context: 507, 1, -4, yes or any of the above? In that regard the other approaches are more intuitive. But like I said, a lot comes down to personal preference. – Leigh Jun 21 '12 at 19:54

DG3 · Answer 2 · 2012-06-18T20:53:27.780

2

Would this help? There will always be better solution than this.

<cfset myList = "">
<cfloop from="1" to="#Arraylen(myArray)#" index="index">

    <Cfif right(myArray[index],3) EQ "yes">
        <cfset myList = listAppend(myList, listFirst(myArray[index], '_'))>
    </Cfif>
</cfloop>

<cfoutput>#myList#</cfoutput>

edited Jun 18 '12 at 20:53

answered Jun 18 '12 at 20:37

DG3

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Do not forget to separate the list elements with commas. Also, `listAppend` is simpler than string concatenation ie `&` – Leigh Jun 18 '12 at 20:41
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FWIW: if you want only the number portion, just split the value inside the loop: ie `myList = listAppend(myList, listFirst(myArray[index], '_'))` – Leigh Jun 18 '12 at 20:47
I got the results like this: 3584_yes 3642_yes 3643_yes but how to convert its list only numbers..(3584,3642,3643) – TGR Jun 18 '12 at 20:50
Good. Do not forget to mark DG3's response as the answer if it solved your problem. – Leigh Jun 18 '12 at 21:23

score 2 · Answer 3 · answered Jun 18 '12 at 22:12

This is partly an extension to Henry answer but should be exactly what your after:

<cfscript>
    tmpArray = ['567_no','584_yes','3642_yes','3643_yes','3644_no','3645_no','3646_no'];
    list = "";
    for (item in tmpArray)
        if (listLast(item, "_") == "yes")
            list = listAppend(list, listFirst(item, "_"));

writeDump(list);

Russ · Answer 4 · 2012-07-02T16:07:07.120

1

Using the Underscore.cfc library (CF 10 only):

filteredArray = _.filter(arguments.ServiceTextArray, function(val) {
    return (val contains 'yes');
});

resultArray = _.map(filteredArray, function(val) {
    return left(val, 4);
});

list = arrayToList(resultArray);

(I created this library, BTW)

edited Jul 02 '12 at 16:07

answered Jul 01 '12 at 08:45

Russ

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Nice one. I did not realize you could do that with CF10. Btw, is that your library? If so, you may want to add the standard affiliation disclaimer to responses [per SO rules](http://stackoverflow.com/faq#promotion). – Leigh Jul 01 '12 at 20:15
Thanks for the info, I've added the disclaimer. Hope you find the library to be useful! – Russ Jul 02 '12 at 16:08

How to (selectively) convert array elements to a list of values

4 Answers4