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How to free memory in Java?
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Java uses managed memory, so the only way you can allocate memory is by using the new operator, and the only way you can deallocate memory is by relying on the garbage collector.
This memory management whitepaper (PDF) may help explain what's going on.
You can also call Sy...
Django filter queryset __in for *every* item in list
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Summary:
One option is, as suggested by jpic and sgallen in the comments, to add .filter() for each category. Each additional filter adds more joins, which should not be a problem for small set of categories.
There is the aggregation approach. This query would be shorter and...
Checking network connection
...t have a working internet connection, the DNS lookup itself may block the call to urllib_request.urlopen for more than a second. Thanks to @rzetterberg for pointing this out.
If the fixed IP address above is not working, you can find a current IP address for google.com (on unix) by running
% dig...
“Keep Me Logged In” - the best approach
...e algorithm that you used. For example:
md5(salt+username+ip+salt)
Now, all an attacker needs to do is brute force the "salt" (which isn't really a salt, but more on that later), and he can now generate all the fake tokens he wants with any username for his IP address! But brute-forcing a salt is...
How do I clone into a non-empty directory?
... will set the upstream branch for you, if that is what you want, and it usually is.
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How can I get the concatenation of two lists in Python without modifying either one? [duplicate]
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Actually you can do this by using the a non hidden function: import operator, operator.add(list1, list2)
– e-satis
Apr 13 '11 at 12:28
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Git in Powershell saying 'Could not find ssh-agent'
I have git installed and it works great in the command prompt, but when I open up powershell it gives me this warning:
6 An...
Bash: Strip trailing linebreak from output
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If your expected output is a single line, you can simply remove all newline characters from the output. It would not be uncommon to pipe to the 'tr' utility, or to Perl if preferred:
wc -l < log.txt | tr -d '\n'
wc -l < log.txt | perl -pe 'chomp'
You can also use command substit...
How to plot two histograms together in R?
...ers. Each data frame has a single numeric column which lists the length of all measured carrots (total: 100k carrots) and cucumbers (total: 50k cucumbers).
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Why does “split” on an empty string return a non-empty array?
...ngleton array containing just the input string is returned,
Second, remove all the rightmost empty strings. This is the reason ",,,".split(",") returns empty array.
According to this, the result of "".split(",") should be an empty array because of the second step, right?
It should. Unfortunately,...