hash from string

[Mage]

Hello,

I have a string like: ' "gaz"=>"1", "viz"=>"1", "lift"=>"0",
"kamra"=>"1", "klima"=>"0" '
Is it possible to convert this easily to hash without calling eval or
writing regexp?

eval is easy and unsecure. Regexp is not very simple if you want handle
every special case (nested values etc).

Mage

 

[Tim Pease]

Hello,

I have a string like: ' "gaz"=>"1", "viz"=>"1", "lift"=>"0",
"kamra"=>"1", "klima"=>"0" '
Is it possible to convert this easily to hash without calling eval
or writing regexp?

eval is easy and unsecure. Regexp is not very simple if you want
handle every special case (nested values etc).

Mage

str = ' "gaz"=>"1", "viz"=>"1", "lift"=>"0", "kamra"=>"1",
"klima"=>"0" '

h = {}
str.split(',').each do |substr|
ary = substr.strip.split('=>')
h[ary.first.tr('"','')] = ary.last.tr('"','')
end


But that won't handle nested values -- that's left for someone else
with more time than me.

Blessings,
TwP

 

[Mage]

str = ' "gaz"=>"1", "viz"=>"1", "lift"=>"0", "kamra"=>"1", "klima"=>"0" '

h = {}
str.split(',').each do |substr|
ary = substr.strip.split('=>')
h[ary.first.tr('"','')] = ary.last.tr('"','')
end


But that won't handle nested values -- that's left for someone else
with more time than me.

Won't even work if any of the values contains a comma.

Mage

 

[Maciej Tomaka]

Won't even work if any of the values contains a comma.

Mage

Why don't you use YAML?
=> "--- \n:qwe: asd\n"
=> {:qwe=>"asd"}


It works for most of things.

 

[Mage]

Why don't you use YAML?

The input string isn't generated by me, and I cannot change its format.

Mage

 

[Avdi Grimm]

eval is easy and unsecure. Regexp is not very simple if you want handle
every special case (nested values etc).

You could try eval with a high SAFE level. Or write a quick parser
using TreeTop.

--
Avdi

Home: http://avdi.org
Developer Blog: http://avdi.org/devblog/
Twitter: http://twitter.com/avdi
Journal: http://avdi.livejournal.com

 

[Michael Morin]

Hello,

I have a string like: ' "gaz"=>"1", "viz"=>"1", "lift"=>"0",
"kamra"=>"1", "klima"=>"0" '
Is it possible to convert this easily to hash without calling eval or
writing regexp?

eval is easy and unsecure. Regexp is not very simple if you want handle
every special case (nested values etc).

Mage

You could do something like this:

#!/usr/bin/env ruby
# UziMonkey <[email protected]>

str = %q{"gaz"=>"1", "viz"=>"1", "lift"=>"0", "kamra"=>"1","klima"=>"0"}

hash = Hash[*
str.
split(/, +/).
map {|s|
s.match( /"([^"]+)"=>"([^"]+)"/ )[1,2]
}.
flatten
]

puts hash.inspect

But the regex makes a lot of assumptions. If the format of the hash
changes at all (for example, quotes removed or changed to single
quotes), it will break. If not, it should work fine.

--
Michael Morin
Guide to Ruby
http://ruby.about.com/
Become an About.com Guide: beaguide.about.com
About.com is part of the New York Times Company

 

[Mage]

You could do something like this:

#!/usr/bin/env ruby
# UziMonkey <[email protected]>

str = %q{"gaz"=>"1", "viz"=>"1", "lift"=>"0", "kamra"=>"1","klima"=>"0"}

hash = Hash[*
str.
split(/, +/).
map {|s|
s.match( /"([^"]+)"=>"([^"]+)"/ )[1,2]
}.
flatten
]

puts hash.inspect

But the regex makes a lot of assumptions. If the format of the hash
changes at all (for example, quotes removed or changed to single
quotes), it will break. If not, it should work fine.

It won't work if any if the values has a comma, like str = ' "gaz" =>
"1", "lift" =>"white, small"'

split(/, +/) will break "white, small"

A much more complicated regexp should work. As far as I see I will stay
with eval.

Mage

 

[Maciej Tomaka]

It won't work if any if the values has a comma, like str = ' "gaz" =>
"1", "lift" =>"white, small"'

split(/, +/) will break "white, small"

A much more complicated regexp should work. As far as I see I will stay
with eval.

Mage

s = str.match(/^\s*\{\s*(.+)\}\s*$/).captures.first;
Hash[*s.scan(/\"([^"]*)\"\s*=>\s*\"([^"]*)\"/).flatten]

Lets assume that each hash is in form:
{ "something" => "someting elswe"[, *] }

Escaped " in strings are not supported here.