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ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.al
I just discovered a logical bug in my code which was causing all sorts of problems. I was inadvertently doing a bitwise AND instead of a logical AND .
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Why does modern Perl avoid UTF-8 by default?
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Set your PERL_UNICODE envariable to AS. This makes all Perl scripts decode @ARGV as UTF‑8 strings, and sets the encoding of all three of stdin, stdout, and stderr to UTF‑8. Both these are global effects, not lexical ones.
At the top of your source file (program, module, l...
Save classifier to disk in scikit-learn
... Works like a charm! I was trying to use np.savez and load it back all along and that never helped. Thanks a lot.
– Kartos
Jan 29 '14 at 9:29
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Show the progress of a Python multiprocessing pool imap_unordered call?
...fully doing a multiprocessing Pool set of tasks with a imap_unordered() call:
9 Answers
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How to set Python's default version to 3.x on OS X?
...n use command python, which will leaving the alias untouched, and works in all shells.
If you launch interpreters more often (I do), you can always create more aliases to add as well, i.e.:
alias 2='python2'
alias 3='python3'
Tip: For scripts, instead of using a shebang like:
#!/usr/bin/env p...
Adding a Method to an Existing Object Instance
...that instance will be passed as the first argument whenever the method is called.
Callables that are attributes of a class (as opposed to an instance) are still unbound, though, so you can modify the class definition whenever you want:
>>> def fooFighters( self ):
... print "fooFighters...
Learning Python from Ruby; Differences and Similarities
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[x*x for x in values if x > 15]
to get a new list of the squares of all values greater than 15. In Ruby, you'd have to write the following:
values.select {|v| v > 15}.map {|v| v * v}
The Ruby code doesn't feel as compact. It's also not as efficient since it first converts the values a...
Virtual Memory Usage from Java under Linux, too much memory used
... a long-standing complaint with Java, but it's largely meaningless, and usually based on looking at the wrong information. The usual phrasing is something like "Hello World on Java takes 10 megabytes! Why does it need that?" Well, here's a way to make Hello World on a 64-bit JVM claim to take over 4...
How to print a int64_t type in C
... hexadecimal.
cppreference.com has a full listing of available macros for all types including intptr_t (PRIxPTR). There are separate macros for scanf, like SCNd64.
A typical definition of PRIu16 would be "hu", so implicit string-constant concatenation happens at compile time.
For your code to ...
How do I check if the Java JDK is installed on Mac?
How do you check if Java SDK is installed on a Mac?
8 Answers
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