Python one-liner to compare two files (conditions apply)

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1 point·vram22··9 comments

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Or do it in a language with lazy I/O and don't worry so much about memory requirements.

import Data.ByteString.Lazy as LBS

areFilesEqual x y = (==) <$> LBS.readFile x <*> LBS.readFile y

(EDIT: added line break)

Nice.

Haskell?

Yes.

function cmp($l, $r) {"$(gc $l)" -eq "$(gc $r)"}

Though, in real life you should compare the lengths of the files before reading them.

I do that in my program - compare lengths first. There's also an interesting comment there by a reader about how filecmp (which can do the job) uses stat info with a cache.

What language is that? shell? and what is gc?

PowerShell. GC is Get-Content. (It's actually horribly inefficient because it tags every line read from the file with half a dozen metadata properties, but it looks good in one-liners.)

or you could just:

diff X Y

and check the return code.

Oh you crazy pythonistas.

You're either trolling, or just didn't / couldn't get that the post was for fun and learning, exploring new/alternative ways of doing things.

> diff X Y

For that matter, doing:

cmp X Y

is even simpler since it doesn't create as much output as diff when the files are different. And hey, we saved one letter over diff. /s

According to your logic, no one should have done an alternative version of a program after the first one for that need was created. The world would be a much poorer place. Only one language, assembly or FORTRAN /COBOL, only one OS, one DB, etc.

Poor fellow - you crazy commenter.

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