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Reshape three column data frame to matrix (“long” to “wide” format) [duplicate]
...y ways to do this. This answer starts with what is quickly becoming the standard method, but also includes older methods and various other methods from answers to similar questions scattered around this site.
tmp <- data.frame(x=gl(2,3, labels=letters[24:25]),
y=gl(3,1,6, labe...
How does this print “hello world”?
...th this codification scheme you can have all 26 (one case) english letters and 6 symbols (being space among them).
Algorithm description
The >>= 5 in the for-loop jumps from group to group, then the 5-bits group gets isolated ANDing the number with the mask 31₁₀ = 11111₂ in the sentenc...
Can I try/catch a warning?
I need to catch some warnings being thrown from some php native functions and then handle them.
11 Answers
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What is memoization and how can I use it in Python?
I just started Python and I've got no idea what memoization is and how to use it. Also, may I have a simplified example?
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Real world use cases of bitwise operators [closed]
...ets
Always involves checksums, parity, stop bits, flow control algorithms, and so on, which usually depend on the logic values of individual bytes as opposed to numeric values, since the medium may only be capable of transmitting one bit at a time.
Compression, Encryption
Both of these are heavily d...
Truncating all tables in a Postgres database
... SELECT tablename FROM pg_tables
WHERE tableowner = username AND schemaname = 'public';
BEGIN
FOR stmt IN statements LOOP
EXECUTE 'TRUNCATE TABLE ' || quote_ident(stmt.tablename) || ' CASCADE;';
END LOOP;
END;
$$ LANGUAGE plpgsql;
This creates a stored function (you n...
How to comment out a block of code in Python [duplicate]
...igns automatically for you. For example, in IDLE on my machine, it's Alt+3 and Alt+4.
Don't use triple-quotes; as you discovered, this is for documentation strings not block comments, although it has a similar effect. If you're just commenting things out temporarily, this is fine as a temporary mea...
Is background-color:none valid CSS?
...en, lime, maroon, navy, olive,
orange, purple, red, silver, teal, white, and yellow
transparent and inherit are valid keywords in their own right, but none is not.
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Mock vs MagicMock
My understanding is that MagicMock is a superset of Mock that automatically does "magic methods" thus seamlessly providing support for lists, iterations and so on... Then what is the reason for plain Mock existing? Isn't that just a stripped down version of MagicMock that can be practically ...
Ideal way to cancel an executing AsyncTask
I am running remote audio-file-fetching and audio file playback operations in a background thread using AsyncTask . A Cancellable progress bar is shown for the time the fetch operation runs.
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