Hello,
I have two txt file,and i want to mix the two files line by line, e.g.
$ cat url1.txt
url1_1.line
url1_2.line
$ cat url2.txt
url2_1.line
url2_2.line
and i want this file as result:
$ cat aha.txt
url1_1.line
url2_1.line
url1_2.line
url2_2.line
i first write
Sun Yi Ming wrote:
Hello,
Hello,
this works fine, but i think if the two file are very big, and the
readFile will consume too many mem.so i need to read the file line by
line but stunned by the loop in IO Monad:
main = do h1 - openFile url1.txt ReadMode
h2 - openFile url2.txt ReadMode
On Wed, Jul 20, 2005 at 02:27:36PM +0800, Sun Yi Ming wrote:
Hello,
I have two txt file,and i want to mix the two files line by line, e.g.
$ cat url1.txt
url1_1.line
url1_2.line
$ cat url2.txt
url2_1.line
url2_2.line
and i want this file as result:
$ cat aha.txt
On Wed, 2005-07-20 at 14:27 +0800, Sun Yi Ming wrote:
[snip]
i first write this snippet of code:
---
import System.IO
mix :: [a] - [a] - [a]
mix [] ys = ys
mix xs [] = xs
mix (x:xs) (y:ys) = [x,y] ++ mix xs ys
f1 = do contents1 - readFile url1.txt
contents2 - readFile
On Wed, 20 Jul 2005, Sun Yi Ming wrote:
mix :: [a] - [a] - [a]
mix [] ys = ys
mix xs [] = xs
mix (x:xs) (y:ys) = [x,y] ++ mix xs ys
mix xs ys = concat (Data.List.transpose [xs,ys])
___
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Arthur van Leeuwen [EMAIL PROTECTED] worte:
Ah, but this is exactly where lazyness wins bigtime: a smart
implementation
of readFile will lazily read the actual file for as far as needed. Thus,
reading with readFile will not read the entire file into memory at once.
What will happen is that
