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What is the difference between the GNU Makefile variable assignments =, ?=, := and +=?
Can anybody give a clear explanation of how variable assignment really works in Makefiles.
6 Answers
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jQuery: select an element's class and id at the same time?
... yes you can specify a selector that has to match ID and class (and potentially tag name and anything else you want to throw in).
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Argparse: Required argument 'y' if 'x' is present
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No, there isn't any option in argparse to make mutually inclusive sets of options.
The simplest way to deal with this would be:
if args.prox and (args.lport is None or args.rport is None):
parser.error("--prox requires --lport and --rport.")
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How many spaces will Java String.trim() remove?
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All of them.
Returns:
A copy of this string with leading and trailing white space removed, or this string if it has no leading or trailing white space.
~ Quoted from Java 1.5.0 docs
(But why didn't you ju...
Classes vs. Modules in VB.NET
...ed solely for helper functions and extension methods and you don't want to allow inheritance and instantiation, you use a Module.
By the way, using Module is not really subjective and it's not deprecated. Indeed you must use a Module when it's appropriate. .NET Framework itself does it many times (...
Batch script loop
...e
for /l %%x in (1, 1, 100) do echo %%x
(which is one of the things I really really hate about windows scripting)
If you have multiple commands for each iteration of the loop, do this:
for /l %x in (1, 1, 100) do (
echo %x
copy %x.txt z:\whatever\etc
)
or in a batch file
for /l %%x in ...
Set time to 00:00:00
...present a moment as it lacks any concept of time zone or offset-from-UTC. Calling LocalDateTime.now almost never makes sense. Use ZonedDateTime instead. Otherwise you are ignoring crucial time zone issues. For one thing, some dates in some zones do not start at 00:00!
– Basil B...
CSS center text (horizontally and vertically) inside a div block
...al align".
Since they tend to be hacks or adding complicated divs... I usually use a table with a single cell to do it... to make it as simple as possible.
Update for 2020:
Unless you need make it work on earlier browsers such as Internet Explorer 10, you can use flexbox. It is widely supported...
Bash script processing limited number of commands in parallel
... the exit status of the last
command waited for. If a job spec is given, all processes in the job
are waited for. If no arguments are given, all currently active child
processes are waited for, and the return status is zero. If neither
jobspec nor pid specifies an active child process of the...
Problem with converting int to string in Linq to entities
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If you call AsEnumerable you will pay a high performance price on larger databases because it will bring everything in memory. IEnumerable is slower in comparison with IQueryable because the later is executed exclusively in the data...