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What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...bar', so loop runs once and
done # prints nothing (actually "")
var="foo bar"
for i in "${var}bar"; do # Expands to 'for i in "foo barbar"; do...'
echo $i # so runs the loop once
done
# foo barbar
Note that "${var}bar" in the second example above could also ...
How to check if a value exists in a dictionary (python)
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it wasn't necesarry after all, unless run on bigger dict. I guess overhead in values() is caused by copying the value list and in viewvalues() by maintaining the view alive.
– soulcheck
Nov 21 '11 at 17:12
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How to dynamic new Anonymous Class?
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All you're doing is saying that dynamic properties are not identical to strongly-typed properties. This is trivially true.
– Steven Sudit
Sep 18 '10 at 2:31
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What's the difference between eval, exec, and compile?
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The short answer, or TL;DR
Basically, eval is used to evaluate a single dynamically generated Python expression, and exec is used to execute dynamically generated Python code only for its side effects.
eval and exec have these two differences:
eval accep...
Passing arguments to “make run”
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What's a macro? Isn't that what people call environment variables? What's the difference between a macro and an environment variable?
– KcFnMi
Aug 12 at 23:05
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How to use filter, map, and reduce in Python 3
... longer return lists:
[...]
map() and filter() return iterators. If you really need a list, a quick fix is e.g. list(map(...)), but a better fix is often to use a list comprehension (especially when the original code uses lambda), or rewriting the code so it doesn’t need a list at all. Particular...
Set select option 'selected', by value
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I had to manually call .val(x).change(); to trigger the select's onChange event, it seems setting val() doesn't fire it.
– scipilot
Jul 19 '15 at 5:48
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How to extract img src, title and alt from html using php? [duplicate]
I would like to create a page where all images which reside on my website are listed with title and alternative representation.
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Python time measure function
...e__, (time2-time1)*1000.0))
return ret
return wrap
Note I'm calling f.func_name to get the function name as a string(in Python 2), or f.__name__ in Python 3.
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Bash if [ false ] ; returns true
...ce "false" is a non-empty string, the test command always succeeds. To actually run the command, drop the [ command.
if false; then
echo "True"
else
echo "False"
fi
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