Logical AND
Performs a logical boolean AND-ing of the two operands returning 1 if both of the operands are non-zero. The logical AND operator is of type int.
0 && 0 /* Returns 0. */
0 && 1 /* Returns 0. */
2 && 0 /* Returns 0. */
2 && 3 /* Returns 1. */
Lo...
Getting the minimum or maximum or using sorted depends on iterations over the object. In the case of dict, the iteration is only over the keys:
adict = {'a': 3, 'b': 5, 'c': 1}
min(adict)
# Output: 'a'
max(adict)
# Output: 'c'
sorted(adict)
# Output: ['a', 'b', 'c']
To keep the dictionary ...
Getting the minimum of a sequence (iterable) is equivalent of accessing the first element of a sorted sequence:
min([2, 7, 5])
# Output: 2
sorted([2, 7, 5])[0]
# Output: 2
The maximum is a bit more complicated, because sorted keeps order and max returns the first encountered value. In case th...
For every infix operator, e.g. + there is a operator-function (operator.add for +):
1 + 1
# Output: 2
from operator import add
add(1, 1)
# Output: 2
even though the main documentation states that for the arithmetic operators only numerical input is allowed it is possible:
from operator impo...
Instead of this lambda-function that calls the method explicitly:
alist = ['wolf', 'sheep', 'duck']
list(filter(lambda x: x.startswith('d'), alist)) # Keep only elements that start with 'd'
# Output: ['duck']
one could use a operator-function that does the same:
from operator import metho...
Grouping the key-value pairs of a dictionary by the value with itemgetter:
from itertools import groupby
from operator import itemgetter
adict = {'a': 1, 'b': 5, 'c': 1}
dict((i, dict(v)) for i, v in groupby(adict.items(), itemgetter(1)))
# Output: {1: {'a': 1, 'c': 1}, 5: {'b': 5}}
which ...
What can be documented?
Examples of functions for various languages.
A brief introduction of each tag.
What is the difference between a question and a topic?
Topics have a broader scope than questions; documentation topics that are asked as a question can be closed because they are too bro...
The Promise.all() static method accepts an iterable (e.g. an Array) of promises and returns a new promise, which resolves when all promises in the iterable have resolved, or rejects if at least one of the promises in the iterable have rejected.
// wait "millis" ms, then resolve with "...
The Promise.race() static method accepts an iterable of Promises and returns a new Promise which resolves or rejects as soon as the first of the promises in the iterable has resolved or rejected.
// wait "milliseconds" milliseconds, then resolve with "value"
function resolve(va...
Arguments are defined in parentheses after the function name:
def divide(dividend, divisor): # The names of the function and its arguments
# The arguments are available by name in the body of the function
print(dividend / divisor)
The function name and its list of arguments are called...
Optional arguments can be defined by assigning (using =) a default value to the argument-name:
def make(action='nothing'):
return action
Calling this function is possible in 3 different ways:
make("fun")
# Out: fun
make(action="sleep")
# Out: sleep
# The argumen...
One can give a function as many arguments as one wants, the only fixed rules are that each argument name must be unique and that optional arguments must be after the not-optional ones:
def func(value1, value2, optionalvalue=10):
return '{0} {1} {2}'.format(value1, value2, optionalvalue1)
Wh...
Arbitrary number of positional arguments:
Defining a function capable of taking an arbitrary number of arguments can be done by prefixing one of the arguments with a *
def func(*args):
# args will be a tuple containing all values that are passed in
for i in args:
print(i)
fun...
<a href="example.com" target="_blank">Text Here</a>
The target attribute specifies where to open the link. By setting it to _blank, you tell the browser to open it in a new tab or window (per user preference).
SECURITY VULNERABILITY WARNING!
Using target="...
A basic join (also called "inner join") queries data from two tables, with their relationship defined in a join clause.
The following example will select employees' first names (FName) from the Employees table and the name of the department they work for (Name) from the Departments table:...
A Left Outer Join (also known as a Left Join or Outer Join) is a Join that ensures all rows from the left table are represented; if no matching row from the right table exists, its corresponding fields are NULL.
The following example will select all departments and the first name of employees that ...
A table may be joined to itself, with different rows matching each other by some condition. In this use case, aliases must be used in order to distinguish the two occurrences of the table.
In the below example, for each Employee in the example database Employees table, a record is returned containi...
The increment and decrement operators exist in prefix and postfix form.
int a = 1;
int b = 1;
int tmp = 0;
tmp = ++a; /* increments a by one, and returns new value; a == 2, tmp == 2 */
tmp = a++; /* increments a by one, but returns old value; a == 3, tmp == 2 */
tmp = --b; ...
