Delete Last Item in A List

[buddhatown]

Very simple question for all you folks out there. I am total noob
with js. I have a list called drawPathList thats just a list of xy
coordinates. I use this to construct a drawing on a map. However,
people would like to be able to 'Undo' something that they have drawn,
so I'd like to yank that last item in a given list.

drawPathList looks like this: 23,34||45,67||456,678||43,78

Can someone help me with a function to remove the last item in the
list (regardless of length)? Thanks all.

 

[Doug Miller]

Very simple question for all you folks out there. I am total noob
with js. I have a list called drawPathList thats just a list of xy
coordinates. I use this to construct a drawing on a map. However,
people would like to be able to 'Undo' something that they have drawn,
so I'd like to yank that last item in a given list.

drawPathList looks like this: 23,34||45,67||456,678||43,78

Can someone help me with a function to remove the last item in the
list (regardless of length)? Thanks all.

Seems to me it would make more sense to implement that as an array of strings,
rather than a single string as you appear to have it now. Then deleting the
nth element from an array of n items is trivial.

 

[buddhatown]

Trivial is the key word here. For now, I think I'm stuck with the
single string, but I'll look at changing how it gets created. If you
have any insight on how to do it with the string, I'd love to hear it.

 

[Bart Van der Donck]

drawPathList looks like this: 23,34||45,67||456,678||43,78

Can someone help me with a function to remove the last item in
the list (regardless of length)?

The usual code:

var drawPathList = ['23,34', '45,67', '456,678', '43,78'];
drawPathList.pop();
alert(drawPathList);

One-dimensional literal solution using a regular expression:

var drawPathList = '23,34||45,67||456,678||43,78||';
drawPathList = drawPathList.replace(/\|\|(,|\d)+$/ ,'');
alert(drawPathList);

Hope this helps,

 

[Evertjan.]

Bart Van der Donck wrote on 09 nov 2007 in comp.lang.javascript:

drawPathList looks like this: 23,34||45,67||456,678||43,78

Can someone help me with a function to remove the last item in
the list (regardless of length)?

The usual code:

var drawPathList = ['23,34', '45,67', '456,678', '43,78'];
drawPathList.pop();
alert(drawPathList);

One-dimensional literal solution using a regular expression:

var drawPathList = '23,34||45,67||456,678||43,78||';
drawPathList = drawPathList.replace(/\|\|(,|\d)+$/ ,'');
alert(drawPathList);

which does not work, as the final || is not detected.

Try:

var x = '23,34||45,67||456,678||43,78||';
x = x.replace(/[,\d]+\|\|$/ ,'');
alert(x);

or

var x = '23,34||45,67||456,678||43,78||';
x = x.split('||');
x.pop();
x.pop();
x.push('');
x = x.join('||');
alert(x);

 

[Bart Van der Donck]

which does not work, as the final || is not detected.

Woops, typing mistake (the original poster wrote it without the last
two pipes).

I added it to test * or + before the $.

/\|\|(,|\d)*$/

should also work for '23,34||45,67||456,678||43,78||'.

Try:

var x = '23,34||45,67||456,678||43,78||';
x = x.replace(/[,\d]+\|\|$/ ,'');
alert(x);

This is suitable for my typing mistake, but not for the OP's
question

 

[Evertjan.]

Bart Van der Donck wrote on 09 nov 2007 in comp.lang.javascript:

Woops, typing mistake (the original poster wrote it without the last
two pipes).

I added it to test * or + before the $.

/\|\|(,|\d)*$/

Ususally writen as:

/\|\|[,\d]*$/

should also work for '23,34||45,67||456,678||43,78||'.

Try:

var x = '23,34||45,67||456,678||43,78||';
x = x.replace(/[,\d]+\|\|$/ ,'');
alert(x);

This is suitable for my typing mistake, but not for the OP's
question

mmm, yes, I should have seen that, Bart.

So this will do:

var x = '23,34||45,67||456,678||43,78';
x = x.split('||');
x.pop();
x = x.join('||');
alert(x);

or

var x = '23,34||45,67||456,678||43,78';
x = x.replace(/\|\|[,\d]*$/ ,'');
alert(x);

 

[Thomas 'PointedEars' Lahn]

(e-mail address removed) said the following on 11/9/2007 1:36 PM:

Quote to learn.

LOL, YMMD.


Regards,

PointedEars

 

[Thomas 'PointedEars' Lahn]

Stuck with a single string? Hmmm.

arrayRef = stringRef.split('||')

var arrayRef = stringRef.split('||');

What string? Now it is an array. You simply remove/delete the last entry.

var lastElem = arrayRef.pop();


PointedEars

 

[buddhatown]

Argh. I omitted something in that original string that I didnt think
would matter, but apparently it does...becasue I cant get any of those
examples to work (but thanks so much for the help)

The string actually looks like this:

var drawPathList = 'm 23,34||45,67||456,678||43,78';

note the m in the beginning and no || at the end.

 

[buddhatown]

Wow. I am embarrassed. Code works fine now. The | were actually
l's. I dont recall ever seeing something delimited with an l...but I
suppose it could make sense since its a line coord. Anyway, thanks to
everyone for the help. My appreciated.

Jason

 

[Evertjan.]

wrote on 12 nov 2007 in comp.lang.javascript:

Wow. I am embarrassed.

Even so:

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