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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[["...
How to make a element expand or contract to its parent container?
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answered Jan 18 '12 at 23:41
robertcrobertc
67.4k1818 gold badges179179 silver badges166166 bronze badges
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C++ include and import difference
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Head GeekHead Geek
32.5k2020 gold badges7272 silver badges8282 bronze badges
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deny directory listing with htaccess
...ood/Test1/ , /public_html/Davood/Test1/Test/ , /public_html/Davood/Test2/ , ...
9 Answers
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Custom error pages on asp.net MVC3
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201
Here's an example of how I handle custom errors. I define an ErrorsController with actions han...
Why is the .bss segment required?
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answered Mar 2 '12 at 15:11
LundinLundin
142k2222 gold badges194194 silver badges315315 bronze badges
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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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JSON formatter in C#?
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answered Aug 24 at 11:36
Gurdeep Singh SidhuGurdeep Singh Sidhu
8655 bronze badges
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