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How can i tell if an object has a key value observer attached
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Put a try catch around your removeObserver call
@try{
[someObject removeObserver:someObserver forKeyPath:somePath];
}@catch(id anException){
//do nothing, obviously it wasn't attached because an exception was thrown
}
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Restoring Nuget References?
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Try re-installing the packages.
In the NuGet Package Manager Console enter the following command:
Update-Package -Reinstall -ProjectName Your.Project.Name
If you want to re-install packages and restore references for the whole soluti...
ssl_error_rx_record_too_long and Apache SSL [closed]
...default_:443>
Error code: ssl_error_rx_record_too_long
This usually means the implementation of SSL on your server is not correct. The error is usually caused by a server side problem which the server administrator will need to investigate.
Below are some things we recommend trying....
UICollectionView current visible cell index
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The method [collectionView visibleCells] give you all visibleCells array you want. Use it when you want to get
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
for (UICollectionViewCell *cell in [self.mainImageCollection visibleCells]) {
NSIndexP...
What is the single most influential book every programmer should read? [closed]
...tt Hargett
How To Solve It by George Polya
The Alchemist by Paulo Coelho
Smalltalk-80: The Language and its Implementation
Writing Secure Code (2nd Edition) by Michael Howard
Introduction to Functional Programming by Philip Wadler and Richard Bird
No Bugs! by David Thielen
Rework by Jason Freid and...
How to convert list of tuples to multiple lists?
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xs, ys = [x for x, y in zs], [y for x, y in zs]
return xs, ys
if __name__ == '__main__':
from timeit import timeit
setup_string='''\
N = 2000000
xs = list(range(1, N))
ys = list(range(N+1, N*2))
zs = list(zip(xs, ys))
from __main__ import t1, t2, t3
'''
print(f'zip:\t\t{timeit(...
Paste multiple columns together
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@baptiste ..possible without do.call?
– Anthony Damico
Jan 28 '13 at 23:11
1
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How to get the original value of an attribute in Rails
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Before rails 5.1
Appending _was to your attribute will give you the previous value.
For rails 5.1+
Copied from Lucas Andrade's answer below: https://stackoverflow.com/a/50973808/9359123
Appending _was is deprecated in rails 5.1, now you should ap...
Pagination in a REST web application
...something there shouldn't be something else on the same URI. If you delete all products of page X - page X may still be valid but contains now the products from page X + 1. So the URI for page X has become the URI for page X + 1 if you see it in "product resource view".
– Fionn...
PHP script - detect whether running under linux or Windows?
...TH_SEPARATOR>":" returns true for Windows too (PATH_SEPARATOR is ":" on all other OSs).
– Titus
Jan 8 '17 at 12:45
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