assignment if key_exist? in Hash

[darren kirby]

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

 

[Peña, Botp]

From: darren kirby [mailto:[email protected]]=20
# > foo =3D some_hash["some_key"] if some_hash.has_key?("some_key")

try,

foo =3D some_hash["some_key"] || foo

kind regards -botp

 

[darren kirby]

quoth the Pe=F1a, Botp:

From: darren kirby [mailto:[email protected]]
# > foo =3D some_hash["some_key"] if some_hash.has_key?("some_key")

try,

foo =3D some_hash["some_key"] || foo

kind regards -botp

That's the one.
Thanks botp,

=2Dd
=2D-=20
darren kirby :: Part of the problem since 1976 :: http://badcomputer.org
"...the number of UNIX installations has grown to 10, with more expected..."
=2D Dennis Ritchie and Ken Thompson, June 1972

 

[ara.t.howard]

foo =3D some_hash["some_key"] || foo

that replaces even if the key is set to 'false', 'nil', or if the has =20=

does not have the key... but prolly what OP wants...


regards.

a @ http://codeforpeople.com/

 

[darren kirby]

quoth the ara.t.howard:

foo =3D 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...=20

I don't understand...If the hash key doesn't exist then foo retains its=20
original value. That is the behaviour I require:

foo =3D "Some String"
h =3D {}
foo =3D h["none_such"] || foo =3D> "Some String"
h =3D {"some_key"=3D>"some value"}
foo =3D h["some_key"] || foo

=3D> "some value"

=2Dd
=2D-=20
darren kirby :: Part of the problem since 1976 :: http://badcomputer.org
"...the number of UNIX installations has grown to 10, with more expected..."
=2D Dennis Ritchie and Ken Thompson, June 1972

 

[Julian Leviston]

What he's saying is if you want to retain the value of "false" or =20
"nil", that won't work too well


Learn about Ruby on Rails! CHECK OUT THE FREE VIDS (LIMITED TIME) NEW =20=

VIDEO OUT 3rd MARCH
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quoth the ara.t.howard:

foo =3D some_hash["some_key"] || foo

that replaces even if the key is set to 'false', 'nil', or if the =20
hash
does not have the key...

I don't understand...If the hash key doesn't exist then foo retains =20=

its
original value. That is the behaviour I require:

foo =3D "Some String"
h =3D {}
foo =3D h["none_such"] || foo =3D> "Some String"
h =3D {"some_key"=3D>"some value"}
foo =3D h["some_key"] || foo

=3D> "some value"

-d
--=20
darren kirby :: Part of the problem since 1976 :: = http://badcomputer.org
"...the number of UNIX installations has grown to 10, with more =20
expected..."
- Dennis Ritchie and Ken Thompson, June 1972

 

[darren kirby]

quoth the Julian Leviston:

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

 

[Daniel DeLorme]

quoth the Julian Leviston:

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)