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Which is more preferable to use: lambda functions or nested functions ('def')?
...= lambda: 0
>>> type(l)
<class 'function'>
>>> def foo(): return 0
...
>>> type(foo)
<class 'function'>
>>> type(foo) is type(l)
True
Since lambdas are functions, they're first-class objects.
Both lambdas and functions:
can be passed around as an...
How do you query for “is not null” in Mongo?
...ist when there is something in the field). Here is a sample data set:
db.foo.find()
{ "_id" : ObjectId("544540b31b5cf91c4893eb94"), "imageUrl" : "http://example.com/foo.jpg" }
{ "_id" : ObjectId("544540ba1b5cf91c4893eb95"), "imageUrl" : "http://example.com/bar.jpg" }
{ "_id" : ObjectId("544540c51b...
Swift Programming: getter/setter in stored property
...rarily wrong, you should wrap a computed property around it.
private var _foo:Int = 0
var foo:Int {
get {
return _foo
}
set {
if(newValue > 999) {
_foo = 999
} else {
_foo = newValue
}
}
}
Or:
private var _foo:Int = 0
var...
Macro vs Function in C
...
#define print(x, y) printf(x y) /* accidentally forgot comma */
print("foo %s", "bar") /* prints "foo %sbar" */
Inline functions and constants help to avoid many of these problems with macros, but aren't always applicable. Where macros are deliberately used to specify polymorphic behavior, uni...
How to return a value from __init__ in Python?
...you want to return an instance variable (or function).
>>> class Foo:
... def __init__(self):
... return 42
...
>>> foo = Foo()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: __init__() should return None
...
node.js shell command execution
...f the data has been read off of stdout. As such, when you run
console.log(foo.stdout);
you get whatever happens to be stored in foo.stdout at the moment, and there's no guarantee what that will be because your child process might still be running.
Second is that stdout is a readable stream, so 1...
jQuery - selecting elements from inside a element
...
You can use any one these [starting from the fastest]
$("#moo") > $("#foo #moo") > $("div#foo span#moo") > $("#foo span") > $("#foo > #moo")
Take a look
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improve this answe...
SQLAlchemy: What's the difference between flush() and commit()?
...
Hopefully this example will make this clearer:
#---
s = Session()
s.add(Foo('A')) # The Foo('A') object has been added to the session.
# It has not been committed to the database yet,
# but is returned as part of a query.
print 1, s.query(Foo).all()
s.commit()
#...
Check whether a variable is a string in Ruby
...return true for instances from derived classes.
class X < String
end
foo = X.new
foo.is_a? String # true
foo.kind_of? String # true
foo.instance_of? String # false
foo.instance_of? X # true
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...
Use git “log” command in another folder
...with the --git-dir parameter, before passing any commands.
git --git-dir /foo/bar/.git log
(Specifying the .git directory is necessary.) From the documentation:
--git-dir=<path>
Set the path to the repository. This can also be controlled by setting the GIT_DIR environment variable....