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How to test if list element exists?
...to check that the name is actually defined in the list:
foo <- list(a=42, b=NULL)
foo
is.null(foo[["a"]]) # FALSE
is.null(foo[["b"]]) # TRUE, but the element "exists"...
is.null(foo[["c"]]) # TRUE
"a" %in% names(foo) # TRUE
"b" %in% names(foo) # TRUE
"c" %in% names(foo) # FALSE
...and foo[["...
Is there any difference between the `:key => “value”` and `key: “value”` hash notations?
...ese are legal:
h = { :$in => array }
h = { :'a.b' => 'c' }
h[:s] = 42
but these are not:
h = { $in: array }
h = { 'a.b': 'c' } # but this is okay in Ruby2.2+
h[s:] = 42
You can also use anything as a key with => so you can do this:
h = { C.new => 11 }
h = { 23 => 'pancakes hous...
Will the base class constructor be automatically called?
Would the age of customer be 2? It seems like the base class's constructor will be called no matter what. If so, why do we need to call base at the end sometimes?
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Eclipse count lines of code
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answered Aug 3 '11 at 10:25
aliopialiopi
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Can you do greater than comparison on a date in a Rails 3 search?
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227
Note.
where(:user_id => current_user.id, :notetype => p[:note_type]).
where("date &g...
How can I stop a Postgres script when it encounters an error?
...om Peter Eisentraut. Thank you, Peter!
http://petereisentraut.blogspot.com/2010/03/running-sql-scripts-with-psql.html
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How to read the Stock CPU Usage data
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answered May 31 '12 at 8:01
nkrnkr
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How to handle invalid SSL certificates with Apache HttpClient? [duplicate]
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edited May 1 '12 at 23:43
Gray
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a...
How to design a database for User Defined Fields?
...cern, I would go with #6... a table per UDF (really, this is a variant of #2). This answer is specifically tailored to this situation and the description of the data distribution and access patterns described.
Pros:
Because you indicate that some UDFs
have values for a small portion of
the overal...