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Python Linked List
...bda lst, el: cons(el, lst), reversed(args), None)
car = lambda lst: lst[0] if lst else lst
cdr = lambda lst: lst[1] if lst else lst
nth = lambda n, lst: nth(n-1, cdr(lst)) if n > 0 else car(lst)
length = lambda lst, count=0: length(cdr(lst), count+1) if lst else count
begin = lambda *args: arg...
How do I add a placeholder on a CharField in Django?
...
do you need to specify forms.TextInput to do the attrs={'placeholder': 'Search'} declaration ?
– JhovaniC
Apr 11 '13 at 20:21
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Using $_POST to get select option value from HTML
... Why is it always better to give values to your <option> tags? "If no value attribute is included, the value defaults to the text contained inside the element". If it works, what's wrong with that?
– osullic
Jan 8 '19 at 15:46
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How to construct a REST API that takes an array of id's for the resources
...resource.
201 Created
Location: "http://example.com/api/batchtask/1254"
Now client can fetch batch response or task progress by polling
GET http://example.com/api/batchtask/1254
This is how others attempted to solve this issue:
Google Drive
Facebook
Microsoft
Subbu Allamaraju
...
How to use putExtra() and getExtra() for string data
...Actually I have a string variable, say str, which stores some string data. Now, I want to send this data from one activity to another activity.
...
Convert a python 'type' object to a string
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print type(someObject).__name__
If that doesn't suit you, use this:
print some_instance.__class__.__name__
Example:
class A:
pass
print type(A())
# prints <type 'instance'>
print A().__class__.__name__
# prints A
Also, it seems there are dif...
What characters are valid for JavaScript variable names?
...t it would be if it weren't for the fact that Unicode escape sequences are now valid in identifiers, too! This is exact according to the ES6 spec: (?:[\p{ID_Start}\$_]|\\u(?:[\dA-Fa-f]{4}|\{[\dA-Fa-f]+\}))([\p{ID_Continue}\$_\u200C\u200D]|\\u(?:[\dA-Fa-f]{4}|\{[\dA-Fa-f]+\}))*
–...
How do I create a constant in Python?
...t declare a variable or value as constant in Python. Just don't change it.
If you are in a class, the equivalent would be:
class Foo(object):
CONST_NAME = "Name"
if not, it is just
CONST_NAME = "Name"
But you might want to have a look at the code snippet Constants in Python by Alex Martelli.
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What is 'Pattern Matching' in functional languages?
...a functional language, the datatypes that you define are usually what are known as discriminated unions or algebraic data types. For instance, what's a (linked) list? A linked list List of things of some type a is either the empty list Nil or some element of type a Consed onto a List a (a list of...
Does MongoDB's $in clause guarantee order
...course will be the natural order or by the selected index order as shown.
If you need to preserve this order, then you basically have two options.
So let's say that you were matching on the values of _id in your documents with an array that is going to be passed in to the $in as [ 4, 2, 8 ].
Appr...