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Creating a zero-filled pandas data frame
... try this:
d = pd.DataFrame(0, index=np.arange(len(data)), columns=feature_list)
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What is a semaphore?
...s bouncers at a nightclub. There are a dedicated number of people that are allowed in the club at once. If the club is full no one is allowed to enter, but as soon as one person leaves another person might enter.
It's simply a way to limit the number of consumers for a specific resource. For exampl...
How can I make a div stick to the top of the screen once it's been scrolled to?
... for. I'd like the element to start at 200px below the top of the page (to allow room for other content) and then once the user has scrolled down become fixed at the top.
– evanr
Aug 1 '09 at 8:10
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What is the “assert” function?
...
assert will terminate the program (usually with a message quoting the assert statement) if its argument turns out to be false. It's commonly used during debugging to make the program fail more obviously if an unexpected condition occurs.
For example:
assert(len...
Making heatmap from pandas DataFrame
...t instead of %matplotlib inline and finish with plt.show() in order to actually see the plot.
– tsveti_iko
Jul 23 '19 at 15:19
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Django Forms: if not valid, show form with error message
...ee. I return the same form that I got in. The error messages have automatically been added to it by the is_valid() function.
– user984003
Feb 1 '13 at 13:57
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FFMPEG (libx264) “height not divisible by 2”
...vcodec libx264 -y -an video.mp4 -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2"
Basically, .h264 needs even dimensions so this filter will:
Divide the original height and width by 2
Round it up to the nearest pixel
Multiply it by 2 again, thus making it an even number
Add black padding pixels up to this num...
When do you use map vs flatMap in RxJava?
...r Exception problem, just throw it with a Non checked exception : RX will call the onError handler for you.
Observable.from(jsonFile).map(new Func1<File, String>() {
@Override public String call(File file) {
try {
return new Gson().toJson(new FileReader(file), Object.c...
What is 'YTowOnt9'?
...e64 encoded PHP-serialized values do too, but when they are empty they are all the same. It makes it look as if a lot of very different PHP scripts have this random string in common.
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Code for decoding/encoding a modified base64 URL
... s.Replace('+', '-'); // 62nd char of encoding
s = s.Replace('/', '_'); // 63rd char of encoding
return s;
}
static byte[] Base64UrlDecode(string arg)
{
string s = arg;
s = s.Replace('-', '+'); // 62nd char of encoding
s = s.Replace('_', '/'); // ...