Tutorial by Examples: l

min(7,2,1,5) # Output: 1 max(7,2,1,5) # Output: 7

You can't pass an empty sequence into max or min: min([]) ValueError: min() arg is an empty sequence However, with Python 3, you can pass in the keyword argument default with a value that will be returned if the sequence is empty, instead of raising an exception: max([], default=42) ...

Arrays can be created by enclosing a list of elements in square brackets ([ and ]). Array elements in this notation are separated with commas: array = [1, 2, 3, 4] Arrays can contain any kind of objects in any combination with no restrictions on type: array = [1, 'b', nil, [3, 4]]

2.0 array = %i(one two three four) Creates the array [:one, :two, :three, :four]. Instead of %i(...), you may use %i{...} or %i[...] or %i!...! Additionally, if you want to use interpolation, you can do this with %I. 2.0 a = 'hello' b = 'goodbye' array_one = %I(#{a} #{b} world) array_tw...

This is the basic use of the <a> (anchor element) element: <a href="http://example.com/">Link to example.com</a> It creates a hyperlink, to the URL http://example.com/ as specified by the href (hypertext reference) attribute, with the anchor text "Link to example...

If you ignore files by using a pattern but have exceptions, prefix an exclamation mark(!) to the exception. For example: *.txt !important.txt The above example instructs Git to ignore all files with the .txt extension except for files named important.txt. If the file is in an ignored folder, y...

In order to access the value of an Optional, it needs to be unwrapped. You can conditionally unwrap an Optional using optional binding and force unwrap an Optional using the ! operator. Conditionally unwrapping effectively asks "Does this variable have a value?" while force unwrapping sa...

Relational operators check if a specific relation between two operands is true. The result is evaluated to 1 (which means true) or 0 (which means false). This result is often used to affect control flow (via if, while, for), but can also be stored in variables. Equals "==" Checks whether...

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 ...

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...

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 &quot...

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...

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...

<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:...

Joins can also be performed by having several tables in the from clause, separated with commas , and defining the relationship between them in the where clause. This technique is called an Implicit Join (since it doesn't actually contain a join clause). All RDBMSs support it, but the syntax is usua...

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 ...