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if A vs if A is not None:
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The statement
if A:
will call A.__nonzero__() (see Special method names documentation) and use the return value of that function. Here's the summary:
object.__nonzero__(self)
Called to implement truth value testing and the built-in operation ...
How update the _id of one MongoDB Document?
I want update an _id field of one document. I know it's not a really good pratice. But with some technical reason, I need update it. If I try to update it I get:
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how to draw smooth curve through N points using javascript HTML5 canvas?
...he resulting line is not smooth. How can I produce a single curve between all the gathered points?
11 Answers
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Which characters are valid in CSS class names/selectors?
What characters/symbols are allowed within the CSS class selectors?
I know that the following characters are invalid , but what characters are valid ?
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How to len(generator()) [duplicate]
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Generators have no length, they aren't collections after all.
Generators are functions with a internal state (and fancy syntax). You can repeatedly call them to get a sequence of values, so you can use them in loop. But they don't contain any elements, so asking for the length of ...
Multiple Models in a single django ModelForm?
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But how? Usually a FormView only has a single form_class assigned to it.
– erikbwork
Oct 7 '16 at 17:42
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Why does GCC generate 15-20% faster code if I optimize for size instead of speed?
... gcc-4.8 1.53s 1.52s -Os
In some cases you can alleviate the effect of disadvantageous optimizations by asking gcc to optimize for your particular processor (using options -mtune=native or -march=native):
Processor Compiler Time (-O2 -mtune=native) Time (-Os...
ElasticSearch: Unassigned Shards, how to fix?
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By default, Elasticsearch will re-assign shards to nodes dynamically. However, if you've disabled shard allocation (perhaps you did a rolling restart and forgot to re-enable it), you can re-enable shard allocation.
# v0.90.x and earlier
curl -XPUT 'localhost:9200/_settings' -d '{
"in...
How to clear the interpreter console?
Like most Python developers, I typically keep a console window open with the Python interpreter running to test commands, dir() stuff, help() stuff , etc.
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Regex to Match Symbols: !$%^&*()_+|~-=`{}[]:";'?,./
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The regular expression for this is really simple. Just use a character class. The hyphen is a special character in character classes, so it needs to be first:
/[-!$%^&*()_+|~=`{}\[\]:";'<>?,.\/]/
You also need to escape the other regular expressio...