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When is del useful in python?
...ly, using del on a local variable makes the intent clearer. Compare:
del foo
to
foo = None
I know in the case of del foo that the intent is to remove the variable from scope. It's not clear that foo = None is doing that. If somebody just assigned foo = None I might think it was dead code. But...
How do I get jQuery to select elements with a . (period) in their ID?
...id selector if the id contains spaces. Use an attribute selector:
$('[id=foo bar]').show();
If possible, specify element type as well:
$('div[id=foo bar]').show();
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How do I remove a property from a JavaScript object?
... delete operator is used to remove properties from objects.
const obj = { foo: "bar" }
delete obj.foo
obj.hasOwnProperty("foo") // false
Note that, for arrays, this is not the same as removing an element. To remove an element from an array, use Array#splice or Array#pop. For example:
arr // [0, ...
Mockito - difference between doReturn() and when()
...fBoundsException (the list is yet empty)
when(spy.get(0)).thenReturn("foo");
//You have to use doReturn() for stubbing:
doReturn("foo").when(spy).get(0);
2. Overriding a previous exception-stubbing:
when(mock.foo()).thenThrow(new RuntimeException());
//Impossible: the exce...
What does the `forall` keyword in Haskell/GHC do?
...
Let's start with a code example:
foob :: forall a b. (b -> b) -> b -> (a -> b) -> Maybe a -> b
foob postProcess onNothin onJust mval =
postProcess val
where
val :: b
val = maybe onNothin onJust mval
This code doesn...
Ruby class instance variable vs. class variable
...(or rather, a subclass of Class) corresponding to it. (When you say class Foo, you're really declaring a constant Foo and assigning a class object to it.) And every Ruby object can have instance variables, so class objects can have instance variables, too.
The trouble is, instance variables on cla...
How to implement “select all” check box in HTML?
...">
function toggle(source) {
checkboxes = document.getElementsByName('foo');
for(var checkbox in checkboxes)
checkbox.checked = source.checked;
}
</script>
<input type="checkbox" onClick="toggle(this)" /> Toggle All<br/>
<input type="checkbox" name="foo" value="bar1...
Unix command-line JSON parser? [closed]
...vailable per default on most *nix operating systems per default.
$ echo '{"foo":1, "bar":2}' | python -m json.tool
{
"bar": 2,
"foo": 1
}
Note: Depending on your version of python, all keys might get sorted alphabetically, which can or can not be a good thing. With python 2 it was the defa...
How does Python 2 compare string and int? Why do lists compare as greater than numbers, and tuples g
...nd a non-numeric type, the numeric type comes first.
>>> 5 < 'foo'
True
>>> 5 < (1, 2)
True
>>> 5 < {}
True
>>> 5 < [1, 2]
True
When you order two incompatible types where neither is numeric, they are ordered by the alphabetical order of their typen...
Python memoising/deferred lookup property decorator
...have cachedproperty:
from boltons.cacheutils import cachedproperty
class Foo(object):
def __init__(self):
self.value = 4
@cachedproperty
def cached_prop(self):
self.value += 1
return self.value
f = Foo()
print(f.value) # initial value
print(f.cached_prop) #...