# Code convention and key word argument
###### tags: `coderschool` `coding convention` `key word argument` `end` `sep`

[TOC]

### 1. Code convention
* Should have 2 lines under Import library
* Function name /variable : camelCase or snake_case
* The class name: PascalCase
* The constant:LIMIT_RATE
* The indentation should be 4 whitespaces.
* Doc string is written under the def function to explain the function Open by """ """.
* The explanation for the code in same line should use 2 whitespaces next to the code.

https://www.python.org/dev/peps/pep-0008/

### 2. Function with key-world argument **kwargs
#### a. Syntax:

`def function_name(arg,*arg,kwarg = "VALUE")`

#### b. Usage:
Using key-world argument WHEN WE DONT KNOW HOW MANY ELEMENT WILL BE CALLED and when adding more argument.
Python also priorise the argument before get the key-word. Therefore, Define the arguments in order .arg --> *arg --> key-word argument.

###### *arg:
also used with iterable to unpack a iteration.

x = (1, 2, 3)
>>> print(*x)

##### **kwarg:
We can provide a default value to an key world argument by using the assignment operator (=).

def foo(a=0, b=1):
  return a + b

>>> foo()
1
>>> foo(1, 2)
3
>>> foo(b=3, a=4)
7

Usually used when we even dont put any argument to call the function
It is also used to in dictionary.

def foo(**kwargs):
 for key, value in kwargs.items():
   print(key, value)

foo(a=1, b=2)
a 1
b 2

### 3. The end parameter VS The sep parameter in print statement
* The end parameter is used to append any string at the end of the output of the print statement

print("Studytonight", end=' ')
print("is awesome")
# Output:
Studytonight is awesome

* 'Sep' arguments passed to the program can be separated by different values.
EX1:

`print("Study", "tonight", sep = ' & ')
#Study & tonight ``

EX2:

print("Studytonight","has","been","created","for", sep = " _ ", end=" _STUDENTS")

#Output:
Studytonight _ has _ been _ created _ for _STUDENTS

**NOTE:**

%%time : to see how long it takes to execute the code