How to generate random strings?

[calif]

Hey!

How can I generate random strings in Go?

I need strings generator, which generates strings with printable bytes
- like a-zA-Z,0-9 and some like !,#,^ etc.

There is a one thing - strings can't be repeated.

How can I do this?

Thanks in advance for Your reply.
Bless.
calif

[roger peppe]

how long should the strings be?

[ptolomy23]

Sounds a lot like a homework assignment, but what the heck.. here's how I'd do it without much thought:

http://pastie.org/1156867

[Rob 'Commander' Pike]

Why use a vector? You know the length, just allocate a slice and range
over its indices. Similarly, why use a buffer rather than a slice of
bytes?

-rob

[ptolomy23]

Valid points.

I used vector and Buffer because I by default reach for containers that grow dynamically; no need to manage indexes or worry about whether the initial sizes are correct. I did realize that I could just use slices right before I sent, though.

New version: http://pastie.org/1156941

It still might get into an infinite loop if you ask for more strings than are possible for a particular size.

It also could generate zero-length strings, and it doesn't use all printable characters.

Probably other issues.

[fango]

printable rings like base64 or URL, so try `encoding` package. If you
don't need determinism, easier to use `crypto/rand` than `rand` for
byte array. Here's a demo:


package main

import (
"crypto/rand"
"encoding/base64"
"fmt"
)

const STRLEN = 80
func main(){
b := make([]byte, STRLEN)
rand.Read(b)
en := base64.StdEncoding // or URLEncoding
d := make([]byte, en.EncodedLen(len(b)))
en.Encode(d, b)
fmt.Printf("src=%s\ndst=%s\n", b, d)
}

[calif]

Hmm, i think about strings generator like this:
http://pastie.org/1158004

How to write it? :)

Thanks in advance.

[Archos]

Some times to learn something new you need to forget what has been
learned.
Forget Python

[calif]

I forget Python, but i wanted to show you what i was talking about. :)

So, can somebody help me?

Thanks in advance.

[ptolomy23]

Ah. Your Python code lists all of the possible strings from the given alphabet of lengths 1..n.

So, in Go you might do something like (attempting to use "product" to keep it similar):

http://pastie.org/1158977

[calif]

This is it!

Thank you very much.

Now i'm reading this code, and trying to understand it. :)

It's great!
Thanks

[Sonia Keys]

On Sep 13, 6:35 pm, ptolomy23 <ptolom...@gmail.com> wrote:
> ...
> New version:http://pastie.org/1156941
> ....

I wrote something similar before seeing your code. I even had the
goto in there at one point, but replaced it with a retry count.

Anyway, http://pastie.org/1159175

[fango]

Is the question about generating permutation of indexes to a string?
then http://cs.utsa.edu/~wagner/knuth/fasc2b.pdf has a thorough study.

Cheers,
Fango