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psql: FATAL: database “” does not exist
... it in the past on other machines but it's giving me some trouble when installing on my macbook. I've installed the application and I ran:
...
Regular vs Context Free Grammars
...ammar is either right or left linear, whereas context free grammar is basically any combination of terminals and non-terminals. Hence you can see that regular grammar is a subset of context-free grammar.
So for a palindrome for instance, is of the form,
S->ABA
A->something
B->something
...
Swift: Pass array by reference?
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@Boon Array is still semantically copied/passed-by-value, but just optimised to use COW.
– eonil
Oct 14 '14 at 3:38
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How can I calculate the difference between two dates?
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Not all days have 86400 seconds. For a trivial example that's fine but it's not a good idea in the real world. DST changes, leap seconds, etc can all mess with it. NSCalendar can tell you how many seconds are in a given day.
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Bulk package updates using Conda
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You want conda update --all.
conda search --outdated will show outdated packages, and conda update --all will update them (note that the latter will not update you from Python 2 to Python 3, but the former will show Python as being outdated if you ...
Generating a unique machine id
...yourself and hash it to an arbitrary length. See the PDF specification for all SMBIOS structures available.
To query the SMBIOS info from Windows you could use EnumSystemFirmwareEntries, EnumSystemFirmwareTables and GetSystemFirmwareTable.
IIRC, the "unique id" from the CPUID instruction is deprec...
Prototypical inheritance - writing up [duplicate]
...bob and ben
The member walk is part of Person.prototype and is shared for all instances bob and ben are instances of Person so they share the walk member (bob.walk===ben.walk).
bob.walk();ben.walk();
Because walk() could not be found on bob directly JavaScript will look for it in the Person.prot...
Use of def, val, and var in scala
...sed:
scala> something = 5 * 6
<console>:8: error: value something_= is not a member of object $iw
something = 5 * 6
^
When the class is defined like:
scala> class Person(val name: String, var age: Int)
defined class Person
and then instantiated with:
scala> def pe...
SQL Server SELECT INTO @variable?
... In case if you aren't using the database type that the OP is using, not all support TOP 1 as Adrian mentioned. SQL Server / MS Access use TOP, MySQL uses LIMIT, and Oracle uses ROWNUM. See w3schools.com/sql/sql_top.asp for more information.
– Tyler
Jul 7 '17...
Linq Query keeps throwing “Unable to create a constant value of type System.Object…”, Why?
...tBindingSource.Position =
accountBindingSource.IndexOf(_dataService.Db.Accounts.First(ac => ac.AccountName == name));
accountBindingSource_CurrentChanged(sender, e);
}
buggy code:
private void onTopAccBtnClick(object sender, EventArgs e)
{
accountBin...