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Python dictionary: Get list of values for list of keys
...n list-comp:
Build list and throw exception if key not found: map(mydict.__getitem__, mykeys)
Build list with None if key not found: map(mydict.get, mykeys)
Alternatively, using operator.itemgetter can return a tuple:
from operator import itemgetter
myvalues = itemgetter(*mykeys)(mydict)
# use ...
Create list of single item repeated N times
I want to create a series of lists, all of varying lengths. Each list will contain the same element e , repeated n times (where n = length of the list).
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How to call asynchronous method from synchronous method in C#?
I have a public async void Foo() method that I want to call from synchronous method. So far all I have seen from MSDN documentation is calling async methods via async methods, but my whole program is not built with async methods.
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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...
Python assigning multiple variables to same value? list behavior
...the same identical value. Variables have types, identities, addresses, and all kinds of stuff like that.
Names don't have any of that. Values do, of course, and you can have lots of names for the same value.
If you give Notorious B.I.G. a hot dog,* Biggie Smalls and Chris Wallace have a hot dog. ...
How to include route handlers in multiple files in Express?
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Actually, the author (TJ Holowaychuck) gives a better approche: vimeo.com/56166857
– avetisk
Mar 23 '13 at 9:36
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How to deep copy a list?
... don't make a deep copy using list() (Both list(...) and testList[:] are shallow copies).
You use copy.deepcopy(...) for deep copying a list.
deepcopy(x, memo=None, _nil=[])
Deep copy operation on arbitrary Python objects.
See the following snippet -
>>> a = [[1, 2, 3], [4, 5, 6]]...
What predefined macro can I use to detect clang?
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To get a list of all the predefined macros that the compiler uses, use this:
clang -dM -E -x c /dev/null
You can do the same for gcc.
share
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Detecting iOS / Android Operating system
... @feeela sometimes the feature is something like being able to install apks, which isn't possible to detect.
– Daniel Lubarov
Mar 7 '16 at 21:11
2
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Is it possible to implement a Python for range loop without an iterator variable?
...ou can just live with the extra i variable.
Here is the option to use the _ variable, which in reality, is just another variable.
for _ in range(n):
do_something()
Note that _ is assigned the last result that returned in an interactive python session:
>>> 1+2
3
>>> _
3
F...