Question on array processing.

Question on array processing.

[Larry P. Schrof]

There is a subscript flag, s:<string> , (used with the 'w' flag) that
allows you to index into a string as if it were an array, using
<string> as a separator for elements.

Here's my question:

I absolutely can NOT figure out how to get zsh to use a single colon (':')
as a separator. No matter how I try to quote the second colon, zsh sees the
second colon in the expression as the termination for the separator string.

I'm tring to do something like:

> str="these:are:some:words"
> echo ${str[(ws:::)2]}
zsh: bad math expression: operand expected at `::)2'

I've also tried :":":, :\::, and :':': - none of those work.

Is this a small flaw / hole in zsh's functionality?

Thanks.
- Larry

Re: Question on array processing.

[Dan Nelson]

In the last episode (Oct 04), Larry P. Schrof said:
> There is a subscript flag, s:<string> , (used with the 'w' flag) that
> allows you to index into a string as if it were an array, using
> <string> as a separator for elements.
> 
> Here's my question:
> 
> I absolutely can NOT figure out how to get zsh to use a single colon
> (':') as a separator. No matter how I try to quote the second colon,
> zsh sees the second colon in the expression as the termination for
> the separator string.
> 
> I'm tring to do something like:
> 
> > str="these:are:some:words"
> > echo ${str[(ws:::)2]}
> zsh: bad math expression: operand expected at `::)2'
> 
> I've also tried :":":, :\::, and :':': - none of those work.
> 
> Is this a small flaw / hole in zsh's functionality?

You can use any character as a delimiter, not just a colon:

$ str="these:are:some:words"
$ echo ${str[(ws/:/)2]}
are

-- 
	Dan Nelson
	dnelson@allantgroup.com

Re: Question on array processing.

[Dan Nelson]

In the last episode (Oct 04), Dan Nelson said:
> In the last episode (Oct 04), Larry P. Schrof said:
> > I'm tring to do something like:
> > 
> > > str="these:are:some:words"
> > > echo ${str[(ws:::)2]}
> > zsh: bad math expression: operand expected at `::)2'
> > 
> > I've also tried :":":, :\::, and :':': - none of those work.
> > 
> > Is this a small flaw / hole in zsh's functionality?
> 
> You can use any character as a delimiter, not just a colon:
> 
> $ str="these:are:some:words"
> $ echo ${str[(ws/:/)2]}
> are

Forgot to include the documentation that mentions this:

       The following flags (except p) are followed by one or more
       arguments as shown.  Any character, or the matching pairs
       `(...)', `{...}', `[...]', or `<...>', may be used in place of a
       colon as delimiters, but note that when a flag takes more than
       one argument, a matched pair of delimiters must surround each
       argument.


-- 
	Dan Nelson
	dnelson@allantgroup.com

Re: Question on array processing.

[Larry P. Schrof]

Awesome - thanks!

Huge favor - could the zshparam man page please be updated to
reflect this? I didn't see anything about it in the subscript flags section.

Also, while I'm requesting updates to the man page, I wanted to point
out a couple of typos I found if anybody wants to correct them.

On the zshparams man page, under the subscript flags section, there is
an identical typo that appears twice:

On the first line of both the 'w' and 'f' subscript flags, the text reads:

"If the parameter subscripted is a scalar than this flag makes"

The 'than' should probably be 'then'. Sorry to be anal. ;)

- Larry

On Wed, Oct 04, 2006 at 03:07:59PM -0500, Dan Nelson wrote:
> In the last episode (Oct 04), Larry P. Schrof said:
> > There is a subscript flag, s:<string> , (used with the 'w' flag) that
> > allows you to index into a string as if it were an array, using
> > <string> as a separator for elements.
> > 
> > Here's my question:
> > 
> > I absolutely can NOT figure out how to get zsh to use a single colon
> > (':') as a separator. No matter how I try to quote the second colon,
> > zsh sees the second colon in the expression as the termination for
> > the separator string.
> > 
> > I'm tring to do something like:
> > 
> > > str="these:are:some:words"
> > > echo ${str[(ws:::)2]}
> > zsh: bad math expression: operand expected at `::)2'
> > 
> > I've also tried :":":, :\::, and :':': - none of those work.
> > 
> > Is this a small flaw / hole in zsh's functionality?
> 
> You can use any character as a delimiter, not just a colon:
> 
> $ str="these:are:some:words"
> $ echo ${str[(ws/:/)2]}
> are
> 
> -- 
> 	Dan Nelson
> 	dnelson@allantgroup.com

Re: Question on array processing.

[Larry P. Schrof]

> Forgot to include the documentation that mentions this:
> 
>        The following flags (except p) are followed by one or more
>        arguments as shown.  Any character, or the matching pairs
>        `(...)', `{...}', `[...]', or `<...>', may be used in place of a
>        colon as delimiters, but note that when a flag takes more than
>        one argument, a matched pair of delimiters must surround each
>        argument.

I didn't see anything about this in zshparams specificially. Would it
be worth mentioning there as well?

Thanks again.