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Operation on every pair of element in a list
...differ:
product() generates every possible pairing of elements, including all duplicates:
1,1 1,2 1,3 1,4
2,1 2,2 2,3 2,4
3,1 3,2 3,3 3,4
4,1 4,2 4,3 4,4
permutations() generates all unique orderings of each unique pair of elements, eliminating the x,x duplicates:
. 1,2 1,3 1,4...
How connect Postgres to localhost server using pgAdmin on Ubuntu?
I installed Postgres with this command
6 Answers
6
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How can I get pg_dump to authenticate properly
...ing host variable PGPASSWORD and .pgpass and neither of these two will allow me to authenticate to the database. I have chmod 'd .pgpass to appropriate permissions and also tried:
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differentiate null=True, blank=True in django
When we add a database field in django we generally write:
18 Answers
18
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advantage of tap method in ruby
...= User.new
user.username = "foobar"
user.save!
they would have to follow all the three lines and then recognize that it is just creating an instance named user.
If it were:
user = User.new.tap do |u|
u.username = "foobar"
u.save!
end
then that would be immediately clear. A reader would not...
source of historical stock data [closed]
I'm trying to make a stock market simulator (perhaps eventually growing into a predicting AI), but I'm having trouble finding data to use. I'm looking for a (hopefully free) source of historical stock market data.
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Mercurial — revert back to old version and continue from there
I'm using Mercurial locally for a project (it's the only repo there's no pushing/pulling to/from anywhere else).
7 Answers
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iOS Simulator failed to install the application
...s the same than remove the app from simulator, but in that case you remove all apps in all simulator.
– xarly
Sep 19 '13 at 9:30
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EXC_BAD_ACCESS signal received
...ou've come from another background it can take a little while before you really internalise the memory management rules - unless you make a big point of it.
Remember, anything you get from an allocation function (usually the static alloc method, but there are a few others), or a copy method, you ow...
Xcode duplicate/delete line
Coming from Eclipse and having been used to duplicate lines all the time, it's pretty strange finding out that Xcode has no such function. Or does it?
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