Hi, i have array with file names
a = ['one.jpg', 'two.txt', 'three.pdf']
how can i sort it that always first value will be *.txt file ?

Thanks, fryt
--
Posted via http://www.ruby-forum.com/.

On Wed, Mar 12, 2008 at 12:02 AM, Ma Fe <frytaz@gmail.com> wrote:
> Hi, i have array with file names
> a = ['one.jpg', 'two.txt', 'three.pdf']
> how can i sort it that always first value will be *.txt file ?
>
> Thanks, fryt
> --
> Posted via http://www.ruby-forum.com/.
>
>

a = ['one.jpg', 'two.txt', 'three.pdf']
#assume you want reverse sort?
a.sort_by {|i| i.scan /\..*?$/}.reverse

You understand, of course, this won't give you .txt as a first hit if
you have a .zip. It simply reverse sorts by the letters following a
dot.

If you just want .txt files, maybe use #select instead...

a.select {|i| i =~ /\..txt$/}

Or you could use #partition if you don't care about the order of other
attributes, but want to hold on to the entire array...

a.partition {|i| i =~ /\..txt$/}.flatten

Todd

well I dont know where in array i have .txt files but its sure that
there is just one and i want to put it at first place of array...
--
Posted via http://www.ruby-forum.com/.

On Wed, Mar 12, 2008 at 12:34 AM, Ma Fe <frytaz@gmail.com> wrote:
> well I dont know where in array i have .txt files but its sure that
> there is just one and i want to put it at first place of array...
> --
>

Try using the #partition method (my last example) then. It gives you
all .txt files at the beginning of the array. I made a mistake
though. There should only be one dot, not two for that (same thing if
you use #select)...

a = ['one.jpg', 'two.txt', 'three.pdf', 'four.txt']
a_new = a.partition {|i| i =~ /\.txt$/}
p a_new

Todd

2008/3/12, Todd Benson <caduceass@gmail.com>:
> On Wed, Mar 12, 2008 at 12:34 AM, Ma Fe <frytaz@gmail.com> wrote:
> > well I dont know where in array i have .txt files but its sure that
> > there is just one and i want to put it at first place of array...
>
> Try using the #partition method (my last example) then. It gives you
> all .txt files at the beginning of the array. I made a mistake
> though. There should only be one dot, not two for that (same thing if
> you use #select)...
>
> a = ['one.jpg', 'two.txt', 'three.pdf', 'four.txt']
> a_new = a.partition {|i| i =~ /\.txt$/}
> p a_new

For the fun of it: here's a solution with #inject:

irb(main):009:0> a = ['one.jpg', 'two.txt', 'three.pdf']
=> ["one.jpg", "two.txt", "three.pdf"]
irb(main):010:0> a.inject([[],[]]) {|(tx,ot),x| (/\.txt$/ =~ x ? tx :
ot) << x;[tx,ot]}.flatten
=> ["two.txt", "one.jpg", "three.pdf"]

There's even a version with *two* #injects:

irb(main):011:0> a.inject([[],[]]) {|(tx,ot),x| (/\.txt$/ =~ x ? tx :
ot) << x;[tx,ot]}.inject {|a,b| a.concat b}
=> ["two.txt", "one.jpg", "three.pdf"]

It's been a while so I *had* to do it. Once in a while I need my
#injection. :-))

Kind regards

robert

--
use.inject do |as, often| as.you_can - without end

a = ['one.jpg', 'two.txt', 'three.pdf','a.txt', 'a.az' , 'a.z']
a_new=a.sort_by do |x|
if x =~ /\.txt$/
0
else
1
end
end
p a_new
--> ["a.txt", "two.txt", "one.jpg", "three.pdf", "a.az", "a.z"]

the sort_by block can be improved surely.
--
Posted via http://www.ruby-forum.com/.

2008/3/12, Rodrigo Bermejo <rodrigo.bermejo@ps.ge.com>:
>
> a = ['one.jpg', 'two.txt', 'three.pdf','a.txt', 'a.az' , 'a.z']
> a_new=a.sort_by do |x|
> if x =~ /\.txt$/
> 0
> else
> 1
> end
> end
> p a_new
> --> ["a.txt", "two.txt", "one.jpg", "three.pdf", "a.az", "a.z"]
>
> the sort_by block can be improved surely.

Here's one way: sorting with priorities:

irb(main):006:0> a = ['one.jpg', 'two.txt', 'three.pdf','a.txt', 'a.az' , 'a.z']
=> ["one.jpg", "two.txt", "three.pdf", "a.txt", "a.az", "a.z"]
irb(main):007:0> a.sort_by {|s| [/\.txt$/=~s ? 0 : 1, s]}
=> ["a.txt", "two.txt", "a.az", "a.z", "one.jpg", "three.pdf"]

;-)

Kind regards

robert

--
use.inject do |as, often| as.you_can - without end

Ma Fe wrote:
> well I dont know where in array i have .txt files but its sure that
> there is just one and i want to put it at first place of array...

> a.select {|i| i =~ /\..txt$/}

That doesn't work.

> b = a.partition {|i| i =~ /\.txt$/}

Neither does that.

This is faster than all the solutions posted so far:


a = ['one.jpg', 'two.kzv', 'a.txt', 'a.az']
new_a = [1]

for elmt in a
if elmt[-3] == ?t
new_a[0] = elmt
else
new_a << elmt
end
end

--output:--
["a.txt", "one.jpg", "two.kzv", "a.az"]
--
Posted via http://www.ruby-forum.com/.