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How to loop backwards in python? [duplicate]
... gives
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
But for iteration, you should really be using xrange instead. So,
xrange(10, 0, -1)
Note for Python 3 users: There are no separate range and xrange functions in Python 3, there is just range, which follows the design of Python 2's xrange.
...
capturing self strongly in this block is likely to lead to a retain cycle
...
Good answer, but I take small issue with you saying: “you can't refer to self or properties on self from within a block that will be strongly retained by self.” This is not strictly true. Please see my answer below. Better to say, “you must take...
Days between two dates? [duplicate]
...est for calendar checks.
from datetime import timedelta, datetime
def cal_days_diff(a,b):
A = a.replace(hour = 0, minute = 0, second = 0, microsecond = 0)
B = b.replace(hour = 0, minute = 0, second = 0, microsecond = 0)
return (A - B).days
if __name__ == '__main__':
x = datetime...
What does |= (ior) do in Python?
...s1 |= s2 # 2
>>> s1.__ior__(s2) # 3
where the final value of s1 is equivalent either by:
an assigned OR operation
an in-place OR operation
an in-place OR operation via special method++
Example
Here we a...
An error occurred while installing pg (0.17.1), and Bundler cannot continue
I just installed Rails 4.0.2 and when creating a new app, in the bundle stage I get:
16 Answers
...
How to merge lists into a list of tuples?
...
In Python 2:
>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> zip(list_a, list_b)
[(1, 5), (2, 6), (3, 7), (4, 8)]
In Python 3:
>>> list_a = [1, 2, 3, 4]
>>> list_b = [5, 6, 7, 8]
>>> list(zi...
Does Swift have documentation generation support?
Many languages support documentation comments to allow a generator (like javadoc or doxygen ) to generate code documentation by parsing that same code.
...
What is the instanceof operator in JavaScript?
...ce p inherits from Person.prototype.
Per the OP's request
I've added a small example with some sample code and an explanation.
When you declare a variable you give it a specific type.
For instance:
int i;
float f;
Customer c;
The above show you some variables, namely i, f, and c. The type...
Getting the last argument passed to a shell script
$1 is the first argument.
$@ is all of them.
27 Answers
27
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ActionController::InvalidAuthenticityToken
...h were page cached. Pages got buffered with a stale authenticity token and all actions using the methods post/put/delete where recognized as forgery attempts. Error (422 Unprocessable Entity) was returned to the user.
The solution for Rails 3:
Add:
skip_before_filter :verify_authenticity_token
...