Assignment if key_exist? in Hash

Ruby
1

Hi all,

I have a bunch of lines like:

foo = some_hash[“some_key”] if some_hash.has_key?(“some_key”)

This feels awkward and cumbersome, so I would imagine there is a more
idiomatic way to write it.

Thanks,
-d

2

From: darren kirby [mailto:[email protected]]

> foo = some_hash[“some_key”] if some_hash.has_key?(“some_key”)

try,

foo = some_hash[“some_key”] || foo

kind regards -botp

3

On Mar 31, 2008, at 9:30 PM, Peña, Botp wrote:

foo = some_hash[“some_key”] || foo

that replaces even if the key is set to ‘false’, ‘nil’, or if the has
does not have the key… but prolly what OP wants…

regards.

a @ http://codeforpeople.com/

4

quoth the Peña, Botp:

From: darren kirby [mailto:[email protected]]

> foo = some_hash[“some_key”] if some_hash.has_key?(“some_key”)

try,

foo = some_hash[“some_key”] || foo

kind regards -botp

That’s the one.
Thanks botp,

-d

5

quoth the ara.t.howard:

On Mar 31, 2008, at 9:30 PM, Peña, Botp wrote:

foo = some_hash[“some_key”] || foo

that replaces even if the key is set to ‘false’, ‘nil’, or if the hash
does not have the key…

I don’t understand…If the hash key doesn’t exist then foo retains its
original value. That is the behaviour I require:

foo = “Some String”
h = {}
foo = h[“none_such”] || foo
=> “Some String”
h = {“some_key”=>“some value”}
foo = h[“some_key”] || foo
=> “some value”

-d

6

What he’s saying is if you want to retain the value of “false” or
“nil”, that won’t work too well

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7

quoth the Julian L.:

What he’s saying is if you want to retain the value of “false” or
“nil”, that won’t work too well

Ahh, OK.

Not a prob. In my use case the hash key will be set to a string or it
will not
exist.

Thanks all,
-d

8

darren kirby wrote:

quoth the Julian L.:

What he’s saying is if you want to retain the value of “false” or
“nil”, that won’t work too well

Ahh, OK.

Not a prob. In my use case the hash key will be set to a string or it will not
exist.

You could also use
foo = hash.fetch(“some_key”, foo)