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How do I print the elements of a C++ vector in GDB?
...db wiki page particularly readable, maybe because it's "slightly" outdated now? For instance, I had the impression that the suggested content of the $HOME/.gdbinit was necessary. At the moment I end up with no such file at all and gdb correctly showing the content of std::vector. However, since duri...
SVN best-practices - working in a team
I'm starting out with SVN. I know the basic commands and understand the base principles. I was wondering if anyone has any tips or best practices for working with Subversion in a team environment.
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Assign multiple columns using := in data.table, by group
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This now works in v1.8.3 on R-Forge. Thanks for highlighting it!
x <- data.table(a = 1:3, b = 1:6)
f <- function(x) {list("hi", "hello")}
x[ , c("col1", "col2") := f(), by = a][]
# a b col1 col2
# 1: 1 1 hi hello
# ...
Detect Chrome extension first run / update
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Updated answer to reflect v3 of manifest:
Chromium now has a chrome.runtime set of APIs, which allow you to fetch the version of the extension.
To get the current version:
chrome.runtime.getManifest().version
To listen when the extension has been first installed, when th...
Nullable Foreign Key bad practice?
Let's say you have a table Orders with a foreign key to a Customer Id. Now, suppose you want to add an Order without a Customer Id, (whether that should be possible is another question) you would have to make the foreign key NULL... Is that bad practice or would you rather work with a link table bet...
For i = 0, why is (i += i++) equal to 0?
...ough decomposition of i += i++ to the parts it is made of requires one to know that both += and ++ are not atomic (that is, neither one is a single operation), even if they look like they are. The way these are implemented involve temporary variables, copies of i before the operations take place - o...
How can I check if a program exists from a Bash script?
...y matter anymore and both type and hash become perfectly safe to use. type now has a -P to search just the PATH and hash has the side-effect that the command's location will be hashed (for faster lookup next time you use it), which is usually a good thing since you probably check for its existence i...
Why is enum class preferred over plain enum?
...color == Card::red_card) line, 4 lines later than the comment (which I see now applies to the first half of the block.) 2 lines of the block gives the bad examples. The first 3 lines are not a problem. The "entire block is why plain enums are bad" threw me as I thought you meant something was wro...
Bogus foreign key constraint fail
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On demand, now as an answer...
When using MySQL Query Browser or phpMyAdmin, it appears that a new connection is opened for each query (bugs.mysql.com/bug.php?id=8280), making it neccessary to write all the drop statements in one query...
Fastest Way to Find Distance Between Two Lat/Long Points
...s of Geometry data types in MyISAM table. As of Mysql 5.7.5, InnoDB tables now also support SPATIAL indices.
Create a SPATIAL index on these points
Use MBRContains() to find the values:
SELECT *
FROM table
WHERE MBRContains(LineFromText(CONCAT(
'('
, @lon + 10 / ( 111.1 / cos...