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Mod of negative number is melting my brain
...
I always use my own mod function, defined as
int mod(int x, int m) {
return (x%m + m)%m;
}
Of course, if you're bothered about having two calls to the modulus operation, you could write it as
int mod(int x, int m) {
int r = x%m;
return r<0 ? r+m : r;
}
or varian...
What's the difference between a proc and a lambda in Ruby?
...rguments passed to it. From ri Kernel#lambda:
Equivalent to Proc.new, except the resulting Proc objects check the number of parameters passed when called.
An example:
p = Proc.new {|a, b| puts a**2+b**2 } # => #<Proc:0x3c7d28@(irb):1>
p.call 1, 2 # => 5
p.call 1 # => NoMethodEr...
Counting the number of True Booleans in a Python List
...True)
2
This is actually more efficient than sum, as well as being more explicit about the intent, so there's no reason to use sum:
In [1]: import random
In [2]: x = [random.choice([True, False]) for i in range(100)]
In [3]: %timeit x.count(True)
970 ns ± 41.1 ns per loop (mean ± std. dev. of...
Check that an email address is valid on iOS [duplicate]
... @"^[A-Z0-9a-z\\._%+-]+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}$";
NSString *laxString = @"^.+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2}[A-Za-z]*$";
NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailReg...
How to perform .Max() on a property of all objects in a collection and return the object with maximu
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We have an extension method to do exactly this in MoreLINQ. You can look at the implementation there, but basically it's a case of iterating through the data, remembering the maximum element we've seen so far and the maximum value it pro...
Convert tuple to list and back
...nswered May 6 '14 at 14:27
KhonixKhonix
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Python strftime - date without leading 0?
...yphen between the % and the letter, you can remove the leading zero.
For example %Y/%-m/%-d.
This only works on Unix (Linux, OS X), not Windows (including Cygwin). On Windows, you would use #, e.g. %Y/%#m/%#d.
share
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Initializing a list to a known number of elements in Python [duplicate]
Right now I am using a list, and was expecting something like:
9 Answers
9
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“for” vs “each” in Ruby
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This is the only difference:
each:
irb> [1,2,3].each { |x| }
=> [1, 2, 3]
irb> x
NameError: undefined local variable or method `x' for main:Object
from (irb):2
from :0
for:
irb> for x in [1,2,3]; end
=> [1, 2, 3]
irb> x
=> 3
With the for loop, ...
Generating matplotlib graphs without a running X server [duplicate]
...b seems to require the $DISPLAY environment variable which means a running X server. Some web hosting services do not allow a running X server session. Is there a way to generate graphs using matplotlib without a running X server?
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