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SQL join: selecting the last records in a one-to-many relationship
...
This is an example of the greatest-n-per-group problem that has appeared regularly on StackOverflow.
Here's how I usually recommend solving it:
SELECT c.*, p1.*
FROM customer c
JOIN purchase p1 ON (c.id = p1.customer_id)
LEFT OUTER JOIN purchase p2 ON (...
Do spurious wakeups in Java actually happen?
...
I read the post and gave me an idea about having unit tests for testing one application's conformance to the looping-wait paradigm by waking it up randomly/deterministically. Or is it already available somewhere?
– akarnokd
Jun 26 '09 at 19...
Else clause on Python while statement
..." expression ":" suite
["else" ":" suite]
This repeatedly tests the expression and, if it is true, executes the first suite; if the expression is false (which may be the first time it is tested) the suite of the else clause, if present, is executed and the loop terminates.
A break s...
Set up DNS based URL forwarding in Amazon Route53 [closed]
....com, instead of myaccount.signin.aws.amazon.com. If you click the link to test the Endpoint URL, AWS will happily redirect your browser to the wrong address!
After noticing your mistake, you will probably edit the <Hostname> in your Redirection Rules to fix the error. Unfortunately, when you...
Print all but the first three columns
...release, GNU Awk 3.1.5) but found here another way: echo ' This is a test' | awk '{print substr($0, index($0,$3))}'
– elysch
Dec 18 '14 at 18:45
1
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The located assembly's manifest definition does not match the assembly reference
I am trying to run some unit tests in a C# Windows Forms application (Visual Studio 2005), and I get the following error:
5...
BeautifulSoup Grab Visible Webpage Text
...rictly the visible text on a webpage. For instance, this webpage is my test case. And I mainly want to just get the body text (article) and maybe even a few tab names here and there. I have tried the suggestion in this SO question that returns lots of <script> tags and html comments wh...
How to colorize diff on the command line?
... 18.04 has diffutils 3.6 and therefore has it.
On 3.5 it looks like this:
Tested with:
diff --color -u \
<(seq 6 | sed 's/$/ a/') \
<(seq 8 | grep -Ev '^(2|3)$' | sed 's/$/ a/')
Apparently added in commit c0fa19fe92da71404f809aafb5f51cfd99b1bee2 (Mar 2015).
Word-level diff
Like diff-high...
Bash tool to get nth line from a file
...probably taken ~12 minutes.
mapfile
I have bash 3.1 and therefore cannot test the mapfile solution.
Conclusion
It looks like, for the most part, it's difficult to improve upon the head tail solution. At best the sed solution provides a ~3% increase in efficiency.
(percentages calculated with th...
How to kill a child process after a given timeout in Bash?
...$!
# Get command PID
while : ; do
PID=$( pgrep -P $SUBSHELL yes )
test "$PID" = "" || break
sleep 1
done
# Open pipe for writing
{ exec 4>finished.pipe ; while : ; do sleep 1000; done } &
read -t 3 FINISHED <finished.pipe
if [ "$FINISHED" = finished ] ; then
echo 'Subpr...