Ruby/Rhomobile: parse directory string representation

Question

I have a string that looks like this: {"whatever-field"=>"gghyduudud"}
I'd like to parse it so that it becomes a hash.

Please help.

Thanks!

That's not a String that's a Hash. In other languages this is also called a Dictionary (key => value). Please elaborate on what you're trying to do. — three, Dec 19 '11 at 14:44
@three I think the string contains `"{\"whatever-field\"=>\"ggh...\"}"` — Allan Nørgaard, Dec 19 '11 at 14:48
@Svarog By dictionary you mean Hash? Afaik "Dictionary" is Python. — Allan Nørgaard, Dec 19 '11 at 14:49
Yeah, I guess hash is what I mean, am pretty new to ruby and come from C#/Java world. And yes, I have a string representation of the hash, and would like to parse it into a hash. — Svarog, Dec 19 '11 at 14:51
Is my answer what you mean? Convert the string representation of the Hash into the actual Hash? — Linuxios, Dec 19 '11 at 14:57

score 1 · Accepted Answer · answered Dec 19 '11 at 15:10

1

You can use eval, but only if the data source is absolutely reliable:

>> eval('{"whatever-field"=>"gghyduudud"}')
=> {"whatever-field"=>"gghyduudud"}

answered Dec 19 '11 at 15:10

tokland

That could be very risky, although it is the only way if it contains other data types. Maybe you can validate the data on a regex first? – Linuxios Dec 19 '11 at 16:12
@Linux_iOS.rb.cpp.c.lisp.m.sh: That's why I said "aboslute reliable". If it comes from a user is no good, if you are sending it your own string it's ok. – tokland Dec 19 '11 at 16:31
Yes. That is why all of the computer literature warns against ever using explicit eval. It seems that `eval` is considered bad practice. Here it makes a lot of sense though. Just thought it was worth mentioning. Of course, if the data must come from outside, you could wrap this in its own thread with a safe level of 4. But that seems a bit cumbersome for just parsing strings. – Linuxios Dec 19 '11 at 17:01

score 0 · Answer 2 · answered Dec 19 '11 at 14:56

0

Here is a solution:

dictionary=Hash[*(dict_str[1..dict_str.length-2].split("=>").map {|strval| strval[1..strval.length-2]})]

That will work as long as you want the keys and values as strings. Its a bit long, but it worked for me.

answered Dec 19 '11 at 14:56

Linuxios

1

`Hash[*(str.delete('{"}').split('=>'))]`is a bit shorter. – steenslag Dec 19 '11 at 15:17
I forget about `delete`. Thanks. – Linuxios Dec 19 '11 at 15:28

2 Answers2