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count the frequency that a value occurs in a dataframe column
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If you want to apply to all columns you can use:
df.apply(pd.value_counts)
This will apply a column based aggregation function (in this case value_counts) to each of the columns.
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Lambda expression to convert array/List of String to array/List of Integers
...the accepted answer are not needed. Streams can be used with lambdas or usually shortened using Method References. Streams enable functional operations. map() converts the elements and collect(...) or toArray() wrap the stream back up into an array or collection.
Venkat Subramaniam's talk (video) e...
npm windows install globally results in npm ERR! extraneous
... be good to share the site.
So far so good, til it comes to the global installing. (Ok, some errors I had to figure out, but now I have working npm).
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Appending a vector to a vector [duplicate]
...end(a), std::begin(b), std::end(b));
The second variant is a more generically applicable solution, as b could also be an array. However, it requires C++11. If you want to work with user-defined types, use ADL:
using std::begin, std::end;
a.insert(end(a), begin(b), end(b));
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Stop/Close webcam which is opened by navigator.getUserMedia
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EDIT
Since this answer has been originally posted the browser API has changed.
.stop() is no longer available on the stream that gets passed to the callback.
The developer will have to access the tracks that make up the stream (audio or video) and stop each of th...
How to escape JSON string?
...r deserializing - rater it is used when you want to create a JSON text manually and you have a C# string and need to gets its proper representation as a text.
– Dror Harari
Dec 30 '14 at 22:50
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How can I “disable” zoom on a mobile web page?
I am creating a mobile web page that is basically a big form with several text inputs.
10 Answers
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Should unit tests be written for getter and setters?
...or handling isn't covered by unit tests it will never be covered. Do you really want to ship a product that contains code that has never ever been run?
– Anders Abel
Jun 1 '11 at 19:10
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How to create a memory leak in Java?
...a thread pool to leak even faster).
The thread loads a class via an (optionally custom) ClassLoader.
The class allocates a large chunk of memory (e.g. new byte[1000000]), stores a strong reference to it in a static field, and then stores a reference to itself in a ThreadLocal. Allocating the extra ...
What is the difference between Flex/Lex and Yacc/Bison?
...itimate copies of (the original, AT&T versions of) Lex and Yacc to install on Ubuntu. I wouldn't necessarily say it is impossible, but I'm not aware of such. Flex and Bison are readily available and are equivalent for most purposes. You may also find various alternative and approximately equi...