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Xcode build failure “Undefined symbols for architecture x86_64”
...ometimes the error "build failure “Undefined symbols for architecture x86_64”" may be caused by this. Because, some libs (not Apple's) were compiled for x32 originally and doesn't support x64.
So what you need, is to change the "Architectures" for your project target like this
NB. If you're us...
What does the “at” (@) symbol do in Python?
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Example
class Pizza(object):
def __init__(self):
self.toppings = []
def __call__(self, topping):
# When using '@instance_of_pizza' before a function definition
# the function gets passed onto 'topping'.
self.toppings.appe...
Why won't my PHP app send a 404 error?
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Your code is technically correct. If you looked at the headers of that blank page, you'd see a 404 header, and other computers/programs would be able to correctly identify the response as file not found.
Of course, your users are still SOL. N...
How to open a new window on form submit
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No need for Javascript, you just have to add a target="_blank" attribute in your form tag.
<form target="_blank" action="http://example.com"
method="post" id="mc-embedded-subscribe-form"
name="mc-embedded-subscribe-form" class="validate"
>
...
Is there any pythonic way to combine two dicts (adding values for keys that appear in both)?
...t;> A + B
Counter({'c': 7, 'b': 5, 'd': 5, 'a': 1})
Counters are basically a subclass of dict, so you can still do everything else with them you'd normally do with that type, such as iterate over their keys and values.
...
In Python how should I test if a variable is None, True or False
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a = 'foo' if a: print 'its true' a is not actually TRUE, it's just not none
– wesm
Apr 3 '15 at 21:06
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Remove a string from the beginning of a string
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Plain form, without regex:
$prefix = 'bla_';
$str = 'bla_string_bla_bla_bla';
if (substr($str, 0, strlen($prefix)) == $prefix) {
$str = substr($str, strlen($prefix));
}
Takes: 0.0369 ms (0.000,036,954 seconds)
And with:
$prefix = 'bla_';
$str = 'bla_string...
Is PHP's count() function O(1) or O(n) for arrays?
Does count() really count the all the elements of a PHP array, or is this value cached somewhere and just gets retrieved?
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C++ Object Instantiation
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On the contrary, you should always prefer stack allocations, to the extent that as a rule of thumb, you should never have new/delete in your user code.
As you say, when the variable is declared on the stack, its destructor is automatically called when it goes out of scope...
Do declared properties require a corresponding instance variable?
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In your interface, you can formally declare an instance variable between the braces, or via @property outside the braces, or both. Either way, they become attributes of the class. The difference is that if you declare @property, then you can implement usin...