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When is -XAllowAmbiguousTypes appropriate?
...he other:
{-# LANGUAGE FlexibleInstances, OverlappingInstances #-}
class Foo a where
whichOne :: a -> String
instance Foo a where
whichOne _ = "a"
instance Foo [a] where
whichOne _ = "[a]"
-- |
-- >>> main
-- [a]
main :: IO ()
main = putStrLn $ whichOne (undefined :: [Int])
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Python constructor and default value [duplicate]
...opyright", "credits" or "license" for more information.
>>> class Foo:
... def __init__(self, x=[]):
... x.append(1)
...
>>> Foo.__init__.__defaults__
([],)
>>> f = Foo()
>>> Foo.__init__.__defaults__
([1],)
>>> f2 = Foo()
>>> Foo.__...
How to convert variable (object) name into String [duplicate]
I have the following data frame with variable name "foo" ;
1 Answer
1
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wget command to download a file and save as a different filename
...com
...
16:07:52 (538.47 MB/s) - `index.html' saved [10728]
vs.
wget -O foo.html google.com
...
16:08:00 (1.57 MB/s) - `foo.html' saved [10728]
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Assigning default values to shell variables with a single command in bash
...
Very close to what you posted, actually:
FOO=${VARIABLE:-default} # If variable not set or null, use default.
Or, which will assign default to VARIABLE as well:
FOO=${VARIABLE:=default} # If variable not set or null, set it to default.
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What is the proper way to check for existence of variable in an EJS template (using ExpressJS)?
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The same way you would do it with anything in js, typeof foo == 'undefined', or since "locals" is the name of the object containing them, you can do if (locals.foo). It's just raw js :p
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In R, how to get an object's name after it is sent to a function?
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Note that for print methods the behavior can be different.
print.foo=function(x){ print(deparse(substitute(x))) }
test = list(a=1, b=2)
class(test)="foo"
#this shows "test" as expected
print(test)
#this (just typing 'test' on the R command line)
test
#shows
#"structure(list(a = 1, b = 2),...
jQuery - Create hidden form element on the fly
...r second question:
$('<input>').attr({
type: 'hidden',
id: 'foo',
name: 'bar'
}).appendTo('form');
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PHP Foreach Pass by Reference: Last Element Duplicating? (Bug?)
... the new value.
So loop 1, the value and $arr[2] become $arr[0], which is 'foo'.
Loop 2, the value and $arr[2] become $arr[1], which is 'bar'.
Loop 3, the value and $arr[2] become $arr[2], which is 'bar' (because of loop 2).
The value 'baz' is actually lost at the first call of the second foreach lo...
How to implement Enums in Ruby?
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Two ways. Symbols (:foo notation) or constants (FOO notation).
Symbols are appropriate when you want to enhance readability without littering code with literal strings.
postal_code[:minnesota] = "MN"
postal_code[:new_york] = "NY"
Constants a...