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Is there any overhead to declaring a variable within a loop? (C++)
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@toto A variable like this could also be nowhere – the var variable is initialized but never used, so a reasonable optimiser can just remove it completely (except the second snippet if the variable was used somewhere after the loop).
– CiaPan...
Python: most idiomatic way to convert None to empty string?
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If you actually want your function to behave like the str() built-in, but return an empty string when the argument is None, do this:
def xstr(s):
if s is None:
return ''
return str(s)
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PHP: If internet explorer 6, 7, 8 , or 9
I want to do a conditional in PHP for the different versions of Internet Explorer along the lines of:
17 Answers
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matplotlib does not show my drawings although I call pyplot.show()
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This answer is old, config should now be in ~/.config/matplotlib/matplotlibrc (for python 3, at least). I just had a related problem, and I think it was caused by using matplotlib in python 2.7, which created a ~/.matplotlib/ directory, and stopped python 3 f...
Get name of caller function in PHP?
...backtrace();
$caller = $trace[1];
echo "Called by {$caller['function']}";
if (isset($caller['class']))
echo " in {$caller['class']}";
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filter for complete cases in data.frame using dplyr (case-wise deletion)
... are a lot of variables and b) impossible when the variable names are not known (e.g. in a function that processes any data.frame).
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【解决】scrapyd启动job时报错：exceptions.TypeError: __init__() got an ...
【解决】scrapyd启动job时报错：exceptions.TypeError: __init__() got an unexpected keyword argument '_job'进入项目spiders目录, 修改 spider py 文件（你自己的spider的主文件）：def __init__(self):改为：def __init__(self, *args, **kwargs):最后不要忘了重新部署一...
Get content uri from file path in android
...IM/Camera/VID_20140312_171146.mp4 But what i was looking for is something different. I need the content:// format URI. The answer from Jinal seems to work perfect
– Ajith Memana
Mar 12 '14 at 11:56
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How do I move to end of line in Vim?
I know how to generally move around in command mode, specifically, jumping to lines, etc. But what is the command to jump to the end of the line that I am currently on?
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What is the best method of handling currency/money?
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If you are using Postgres (and since we're in 2017 now) you might want to give their :money column type a try.
add_column :products, :price, :money, default: 0
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