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Python `if x is not None` or `if not x is None`?
... fall in this one.
>>> not x
False
You may be interested to see what literals are evaluated to True or False in Python:
Truth Value Testing
Edit for comment below:
I just did some more testing. not x is None doesn't negate x first and then compared to None. In fact, it seems the i...
“Origin null is not allowed by Access-Control-Allow-Origin” error for request made by application ru
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So what is the solution to this?
– jQuerybeast
Dec 9 '11 at 21:04
19
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JPA - Returning an auto generated id after persist()
... NB: this needs to anotate the id field with @GeneratedValue - whatever that entails
– Mr_and_Mrs_D
Feb 8 '14 at 20:12
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How to get an enum value from a string value in Java?
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What exactly do you mean by "are created at compile time and do not appear in source code." ?
– treesAreEverywhere
Mar 7 '14 at 0:43
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leiningen - how to add dependencies for local jars?
...s and the like in Clojure space, see the Leiningen, Clojure and libraries: what am I missing? thread on the Clojure Google group. Many participants specifically mention the need to have local dependencies not contained in any repositories, local or otherwise, and elaborate on the solutions they've c...
Check if all elements in a list are identical
...es the list is non-empty (but that's trivial to check, and decide yourself what the outcome should be on an empty list)
x.count(x[0]) == len(x)
some simple benchmarks:
>>> timeit.timeit('len(set(s1))<=1', 's1=[1]*5000', number=10000)
1.4383411407470703
>>> timeit.timeit('len...
Total memory used by Python process?
...y using? I've seen discussions about memory usage for a single object, but what I need is total memory usage for the process, so that I can determine when it's necessary to start discarding cached data.
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How to compile a 32-bit binary on a 64-bit linux machine with gcc/cmake
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What does export mean? Where does it belong? Te header files? The makefile? Nope, totally not an answer for me as a beginner.
– Tomáš Zato - Reinstate Monica
Sep 29 '15 at 10:09
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Saving interactive Matplotlib figures
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Somewhat surprised this isn't implemented.. But ok, I'll save the processed data in an intermediate file and send that and a script for plotting to colleagues. Thanks.
– Matt
Dec 6 '10 at ...
How to insert an element after another element in JavaScript without using a library?
...e appendChild() Method, e.g. existingElement.appendAfter(newElement);. See what I mean at this updated jsfiddle.
– stomtech
May 25 '17 at 9:43
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