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delete_all vs destroy_all?
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80
It should also be noted that 1) Callbacks are not called when using delete_all, and 2) destroy_all instantiates all the records and destroys...
How can I see the size of files and directories in linux? [closed]
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answered Jul 30 '12 at 10:59
mk..mk..
14.1k1313 gold badges5757 silver badges9090 bronze badges
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How to merge a transparent png image with another image using PIL
....png")
foreground = Image.open("test2.png")
background.paste(foreground, (0, 0), foreground)
background.show()
First parameter to .paste() is the image to paste. Second are coordinates, and the secret sauce is the third parameter. It indicates a mask that will be used to paste the image. If you p...
cannot load such file — zlib even after using rvm pkg install zlib
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201
I ended up installing zlib from apt-get and then reinstalling ruby to not use the rvm directory...
Get Image size WITHOUT loading image into memory
...e operations in the source like:
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prefix = fp.read(16)
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fp.seek(0)
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but these hardly constitute reading the whole file. In fact .open simply returns a file object and the filename on success. In addition the docs say:
open(file, mode=”r”)
Opens and identifies the given ...
What is an intuitive explanation of the Expectation Maximization technique? [closed]
... parameters:
import numpy as np
from scipy import stats
np.random.seed(110) # for reproducible results
# set parameters
red_mean = 3
red_std = 0.8
blue_mean = 7
blue_std = 2
# draw 20 samples from normal distributions with red/blue parameters
red = np.random.normal(red_mean, red_std, size=20)
b...
Convert base-2 binary number string to int
...ser_name
29.3k3939 gold badges113113 silver badges180180 bronze badges
answered Jan 19 '12 at 15:02
unwindunwind
353k5959 gold bad...
Warning: Null value is eliminated by an aggregate or other SET operation in Aqua Data Studio
...ult is display.
How to solve this problem?. How to change the null data to 0 when no data in the table?.
6 Answers
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Test whether string is a valid integer
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[[ $var =~ ^-?[0-9]+$ ]]
The ^ indicates the beginning of the input pattern
The - is a literal "-"
The ? means "0 or 1 of the preceding (-)"
The + means "1 or more of the preceding ([0-9])"
The $ indicates the end of the input pattern
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CSS to set A4 paper size
... the width of ~196mm and then scale the whole content up to the width of 210mm ~ but strangely exactly the same scaling factor is applied to contents with any width smaller than 210mm).
To fix this problem you can simply in the print media rule assign the A4 paper width and hight to html, body or di...