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JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images
...efore actually uploading it. The demo does neither. It simply takes a file from a file input and displays it the right way, when is this useful in the real world? When I parse my page and feed the URLs from the image tags into the loadImage library there is no exif data so can't do that. For the upl...
Pandas: drop a level from a multi-level column index?
...
You can use MultiIndex.droplevel:
>>> cols = pd.MultiIndex.from_tuples([("a", "b"), ("a", "c")])
>>> df = pd.DataFrame([[1,2], [3,4]], columns=cols)
>>> df
a
b c
0 1 2
1 3 4
[2 rows x 2 columns]
>>> df.columns = df.columns.droplevel()
>>...
How can I convert an RGB image into grayscale in Python?
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How about doing it with Pillow:
from PIL import Image
img = Image.open('image.png').convert('LA')
img.save('greyscale.png')
Using matplotlib and the formula
Y' = 0.2989 R + 0.5870 G + 0.1140 B
you could do:
import numpy as np
import matplotlib.pypl...
Why does the month argument range from 0 to 11 in JavaScript's Date constructor?
... using the below call, I found out that the month argument counts starting from zero.
8 Answers
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Generate a random point within a circle (uniformly)
...es simply by picking an angle theta. So we now need to generate a distance from the center by picking a point in the sliver ABC. Again, extend to ABCD, where D is now twice the radius from the circle center.
Picking a random point in ABCD is easy using the above method. Pick a random point on AB. U...
Sort points in clockwise order?
...* (a.y - center.y)
if the result is zero, then they are on the same line from the center, if it's positive or negative, then it is on one side or the other, so one point will precede the other.
Using it you can construct a less-than relation to compare points and determine the order in which they ...
Determine distance from the top of a div to top of window with javascript
...elementOffset - scrollTop);
The distance variable now holds the distance from the top of the #my-element element and the top-fold.
Here is a demo: http://jsfiddle.net/Rxs2m/
Note that negative values mean that the element is above the top-fold.
...
What's the best way to send a signal to all members of a process group?
...ocess group. (This is often the case if the tree is the result of forking from a server start or a shell command line.) You can discover process groups using GNU ps as follows:
ps x -o "%p %r %y %x %c "
If it is a process group you want to kill, just use the kill(1) command but instead of giv...
How do I install an R package from source?
...o try it. However, the first step is to installed a package called RJSONIO from source.
6 Answers
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What is the most efficient way of finding all the factors of a number in Python?
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from functools import reduce
def factors(n):
return set(reduce(list.__add__,
([i, n//i] for i in range(1, int(n**0.5) + 1) if n % i == 0)))
This will return all of the factors, very quickly, of a n...