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How to apply a function to two columns of Pandas dataframe
...dex the Series to get the values needed.
In [49]: df
Out[49]:
0 1
0 1.000000 0.000000
1 -0.494375 0.570994
2 1.000000 0.000000
3 1.876360 -0.229738
4 1.000000 0.000000
In [50]: def f(x):
....: return x[0] + x[1]
....:
In [51]: df.apply(f, axis=1) #passes...
How to crop an image in OpenCV using Python
...)
crop_img = img[y:y+h, x:x+w]
cv2.imshow("cropped", crop_img)
cv2.waitKey(0)
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How do I get indices of N maximum values in a NumPy array?
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edited Aug 2 '11 at 10:45
answered Aug 2 '11 at 10:32
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Delete element in a slice
... arguments to a variadic function.
So what this line does:
a = append(a[:0], a[1:]...)
is essentially:
a = append(a[:0], a[1], a[2])
Now, you may be wondering, why not just do
a = append(a[1:]...)
Well, the function definition of append is
func append(slice []Type, elems ...Type) []Type
...
Is False == 0 and True == 1 an implementation detail or is it guaranteed by the language?
Is it guaranteed that False == 0 and True == 1 , in Python (assuming that they are not reassigned by the user)? For instance, is it in any way guaranteed that the following code will always produce the same results, whatever the version of Python (both existing and, likely, future ones)?
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Do you use NULL or 0 (zero) for pointers in C++?
...as bolted on top of C, you could not use NULL as it was defined as (void*)0 . You could not assign NULL to any pointer other than void* , which made it kind of useless. Back in those days, it was accepted that you used 0 (zero) for null pointers.
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How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops
...ns:
- Range.
E.g. a-z matches an lower case letters from a to z
E.g. 0-5 matches any number from 0 to 5
[] Match exactly one of the objects inside these brackets.
E.g. [a] matches the letter a
E.g. [abc] matches a single letter which can be a, b or c
E.g. [a-z] matches any single lower cas...
Android emulator-5554 offline
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edited Aug 8 '19 at 9:50
louloulfx
4588 bronze badges
answered Jan 24 '14 at 10:27
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What does `kill -0 $pid` in a shell script do?
Basically, what signal does '0' represent, because here I see SIGNAL numbers starting from 1.
6 Answers
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Is it possible to declare two variables of different types in a for loop?
...tax has been supported in gcc and clang for years (since gcc-7 and clang-4.0) (clang live example). This allows us to unpack a tuple like so:
for (auto [i, f, s] = std::tuple{1, 1.0, std::string{"ab"}}; i < N; ++i, f += 1.5) {
// ...
}
The above will give you:
int i set to 1
double f set...