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Test if lists share any items in python
... generally the fastest.
There are four common ways to test if two lists a and b share any items. The first option is to convert both to sets and check their intersection, as such:
bool(set(a) & set(b))
Because sets are stored using a hash table in Python, searching them is O(1) (see here for...
What do the plus and minus signs mean in Objective-C next to a method?
In Objective-C, I would like to know what the + and - signs next to a method definition mean.
4 Answers
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Printing a variable memory address in swift
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Swift 2
This is now part of the standard library: unsafeAddressOf.
/// Return an UnsafePointer to the storage used for `object`. There's
/// not much you can do with this other than use it to identify the
/// object
Swift 3
For Swift 3, use withUnsafeP...
Sell me on const correctness
... be changed,
It protects you from making accidental variable assignments, and
The compiler can optimize it. For instance, you are protected from
if( x = y ) // whoops, meant if( x == y )
At the same time, the compiler can generate more efficient code because it knows exactly what the state of...
Generate a Hash from string in Javascript
...same as hash * 31 + char but a LOT faster. It's nice because it's so fast, and 31 is a small prime. Win win there.
– corsiKa
Sep 30 '11 at 21:59
43
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What are the use(s) for tags in Go?
...ues of struct fields. Basically we need to acquire the Type of our struct, and then we can query fields e.g. with Type.Field(i int) or Type.FieldByName(name string). These methods return a value of StructField which describes / represents a struct field; and StructField.Tag is a value of type Struct...
Combining two expressions (Expression)
I have two expressions of type Expression<Func<T, bool>> and I want to take to OR, AND or NOT of these and get a new expression of the same type
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Python dictionary: are keys() and values() always the same order?
It looks like the lists returned by keys() and values() methods of a dictionary are always a 1-to-1 mapping (assuming the dictionary is not altered between calling the 2 methods).
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Database design for audit logging
...d that is used by a few wiki platforms is to separate the identifying data and the content you're auditing. It adds complexity, but you end up with an audit trail of complete records, not just listings of fields that were edited that you then have to mash up to give the user an idea of what the old...
How do I use itertools.groupby()?
I haven't been able to find an understandable explanation of how to actually use Python's itertools.groupby() function. What I'm trying to do is this:
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