2/27 In perl, say I have a @list of strings, how do I print the first
character of those stings, concatinated? For example, if @list is
['hello','world',123], I want an output of hw1. I can do a loop,
substr, and the .= operator, but it looks lame...
\_ what's wrong with just doing what works?
\_ TMTOWTDIT, but foreach $item (@array) { print substr($item,0,1) }
is one way. -tom
\_ map { print substr($_,0,1) } @array
or
$output = map { substr($_,0,1) } @array
\_ The latter doesn't work, because it calls map in scalar
context; you need $output = join "", map { substr($_,0,1) }
@array.
\_ (dolist (i array)(print (char i 0))) -- ilyas
\_ gee you're clever.
\_ Array.map (fun x -> print_char x.[0]) array
p([[X|_]|Y]):-print(X),p(Y).
Incidentally, I know of multiple cases where a Perl
programmer benefitted from seeing a solution in another
language. But I respect your anonymous snide remark
anyways. -- ilyas
\_ Because we all know that anyone posting anonymously
is also less intelligent and has invalid points. I
post anonymously to cloak my inferiority to you and
others who are so smart because you sign your names.
Really, it's just jealousy. Anonymity is a form of
envy. I think I'll start signing all my posts so I
envy. I think I'll start signing all my posts so I
anyways. -- ilyas
can be just as smart and well likde as you!
can be just as smart and well liked as you! -- ilyas
\_ you're pathetic. -intelligent, valid anonymous guy
\_ wow I can't believe how many ways there are to do this.
Here is the ultimate question. After parsing, internal
representation, and optimization in Perl, which one of the
above gives you the quickest runtime?
\_ Depends on the size of your array. Generally map is faster
as length @array gets larger.
\_ what are you implying, that the function "foreach"
expands the representations in memory (extra malloc
maybe?) and then goes through the elements? For
example "foreach $a (1..10000)" does an expansion,
and that "foreach $a list" does the same thing?
\_ I'm not implying anything. Everything I say is
emperical experience. I leave the internals as
an exercise to the reader.
\_ That's all bullshit.
array.each {|i| print i[0].chr}
\_ Prolog is shorter:
p([[X|_]|Y]):-print(X),p(Y). -- ilyas
\_ I'm not convinced that's really shorter. How is that used? I
don't know much about Prolog. Given a list called "Array",
how do you print it?
\_ p(Array). -- ilyas
\_ As I suspected. So it ain't shorter!
\_ In some sense, 'array' in your code and
'[[X|_]|Y]' in mine are equivalent. Both are
internal variable names for some data. What you were
asking me to do is something else, namely provide
a function call wrapper to the code, which isn't what
your code does. I think the original stands as an
equivalent to yours. -- ilyas
\_ In some sense, that code and your code are
given the same input. You rule!
equivalent because they produce the same output
given the same input. You rule! -- ilyas
\_ Well I could say
[].each{|i|putc i[0].chr}
\_ Given an array "array", it prints the characters.
It's a function call. No? (It's ruby, for anyone
who doesn't know...)
\_ Given an array "[[X|_]|Y]", it prints the
characters. Prolog names can have structure
built in. -- ilyas
\_ cool. btw i shortened it again.
array.each {|i| print i[0].chr}
built in. -- ilyas
\_ Well I could say
[].each{|i|putc i[0]}
[].map{|i|putc i[0]}
Is that longer than Prolog? I'm no ruby
expert so I'm not sure if there's anything
better there.
\_ Yup, you win. You can look here for more
examples me, dbushong and some others
came up with:
http://www.bushong.net/david/comparisons
\_ cool. btw i shortened it again.
\_ you rock! -- ilyas
-- ilyas
\_ cool. btw i shortened it again(2) |
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