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When should I use nil and NULL in Objective-C?
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edited Jan 27 '16 at 14:15
community wiki
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How to fix the uninitialized constant Rake::DSL problem on Heroku?
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205
Put this in your Rakefile above require 'rake':
require 'rake/dsl_definition'
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Bytes of a string in Java
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291
A string is a list of characters (i.e. code points). The number of bytes taken to represent t...
JavaScript Regular Expression Email Validation [duplicate]
...ine it as a regular expression:
var pattern = /^\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,3}$/;
BTW, please don't validate email addresses on the client-side. Your regular expression is way too simple to pass for a solid implementation anyway.
See the real thing here: http://www.ex-parrot.com/~pdw/Mail-RFC...
Should all Python classes extend object?
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In Python 2, not inheriting from object will create an old-style class, which, amongst other effects, causes type to give different results:
>>> class Foo: pass
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>>> type(Foo())
<type 'instance'>
vs.
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Convert tuple to list and back
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298
Convert tuple to list:
>>> t = ('my', 'name', 'is', 'mr', 'tuple')
>>> t
('...
Can grep show only words that match search pattern?
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Dan MidwoodDan Midwood
14.1k33 gold badges2626 silver badges3131 bronze badges
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What does `kill -0 $pid` in a shell script do?
... then no signal is sent, but error checking is still performed.
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kill(2)
$ man 2 kill
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If sig is 0, then no signal is sent, but error checking is still performed; this
can be used to check for the existence of a process ID or process group ID.
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Best way to convert strings to symbols in hash
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