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How to reshape data from long to wide format
...ckage:
library(sqldf)
sqldf('SELECT name,
MAX(CASE WHEN numbers = 1 THEN value ELSE NULL END) x1,
MAX(CASE WHEN numbers = 2 THEN value ELSE NULL END) x2,
MAX(CASE WHEN numbers = 3 THEN value ELSE NULL END) x3,
MAX(CASE WHEN numbers = 4 THEN value ELSE NULL END) x4
FRO...
mysql -> insert into tbl (select from another table) and some default values [duplicate]
...
If you want to insert all the columns then
insert into def select * from abc;
here the number of columns in def should be equal to abc.
if you want to insert the subsets of columns then
insert into def (col1,col2, col3 ) select scol1,scol2,scol3 from abc; ...
How do I edit an incorrect commit message in git ( that I've pushed )?
...9143a9 - a6fd86 - 5a6057 [master]
\
b886a0 [temp]
Then, cherry-pick all the commit that is ahead of 946992 from master to temp and commit them, use amend if you want to change their messages as well:
git cherry-pick 9143a9
git commit --amend -m "<new_message>
...
git ...
What is JavaScript garbage collection?
...o scope and off the scav list when
they go out of scope.
Every now and then the garbage
collector runs. First it puts a
"mark" on every object, variable,
string, etc – all the memory tracked
by the GC. (JScript uses the VARIANT
data structure internally and there
are plenty of e...
Website screenshots
Is there any way of taking a screenshot of a website in PHP, then saving it to a file?
26 Answers
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IntelliJ inspection gives “Cannot resolve symbol” but still compiles code
... | Invalidate Caches and if it doesn't help, delete IDEA system directory. Then re-import the Maven project and see if it helps.
In some weird cases compiled classes may report wrong info and confuse IDEA. Verify that the classes from this jar report correct names using javap.
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PG::ConnectionBad - could not connect to server: Connection refused
...led pg (gem uninstall pg), uninstalled postgres (brew uninstall postgres), then nuked the postgres folder which was lingering with a bunch of stale stuff it in (rm -rf /usr/local/var/postgres). After a reboot brew install postgres, ln -sfv /usr/local/opt/postgresql/*.plist ~/Library/LaunchAgents, la...
Quickly reading very large tables as dataframes
...bed in JD Long's answer, imports data into a temporary SQLite database and then reads it into R. See also: the RODBC package, and the reverse depends section of the DBI package page. MonetDB.R gives you a data type that pretends to be a data frame but is really a MonetDB underneath, increasing perf...
How to break out from a ruby block?
...k to exit immediately, returning control to the iterator method, which may then begin a new iteration by invoking the block again:
f.each do |line| # Iterate over the lines in file f
next if line[0,1] == "#" # If this line is a comment, go to the next
puts eval(line)
end
When ...
git stash changes apply to new branch?
I was working on master branch, made some changes and then stashed them. Now, my master is at HEAD.
3 Answers
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