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Unique constraint that allows empty values in MySQL
...
Yes, you can do this. See the MySQL reference (version 5.5).
A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. For all engines, a UNIQUE index allows multiple NULL v...
What is the minimum I have to do to create an RPM file?
...%{name}-%{version}-%{release}-root
%description
%{summary}
%prep
%setup -q
%build
# Empty section.
%install
rm -rf %{buildroot}
mkdir -p %{buildroot}
# in builddir
cp -a * %{buildroot}
%clean
rm -rf %{buildroot}
%files
%defattr(-,root,root,-)
%config(noreplace) %{_sysconfdir}/%{name}/%{nam...
Select row with most recent date per user
...posted by Justin, may be more optimal. The accepted answer uses a backward index scan on the primary key of the table, followed by a limit, followed by a sequence scan of the table. Therefore, the accepted answer can be greatly optimized with an additional index. This query could be optimized by an ...
Python list subtraction operation
...ting and using bisect:
ys = sorted(y)
def bisect_contains(seq, item):
index = bisect.bisect(seq, item)
return index < len(seq) and seq[index] == item
[item for item in x if bisect_contains(ys, item)]
If your items are neither hashable nor comparable, then you're stuck with the quadra...
How do I pass command line arguments to a Node.js program?
...ine arguments.
// print process.argv
process.argv.forEach(function (val, index, array) {
console.log(index + ': ' + val);
});
This will generate:
$ node process-2.js one two=three four
0: node
1: /Users/mjr/work/node/process-2.js
2: one
3: two=three
4: four
...
How to view the list of compile errors in IntelliJ?
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I think this comes closest to what you wish:
(From IntelliJ IDEA Q&A for Eclipse Users):
The above can be combined with a recently introduced option in Compiler settings to get a view very similar to that of Eclipse.
Things to do:
Switch to 'Problems' view in the Project pane: ...
Dictionary returning a default value if the key does not exist [duplicate]
... DictionaryWithDefault object is upcast to a plain Dictionary, calling the indexer will use the base Dictionary implementation (throwing an exception if missing) rather than the subclass's implementation.
share
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C#: Raising an inherited event
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I had some issues implementing this... stackoverflow.com/q/10593632/328397
– goodguys_activate
May 15 '12 at 3:07
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Why does a RegExp with global flag give wrong results?
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A RegExp object with the g flag keeps track of the lastIndex where a match occurred, so on subsequent matches it will start from the last used index, instead of 0. Take a look:
var query = 'Foo B';
var re = new RegExp(query, 'gi');
var result = [];
result.push(re.test('Foo Ba...
A weighted version of random.choice
...: a must be 1-dimensional"), so in that case one can ask numpy to pick the index into the list, i.e. len(list_of_candidates), and then do list_of_candidates[draw]
– xjcl
Mar 17 '19 at 23:17
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