I do think writing blogs is a good way to conclude what you have learned so far. That’s also why I decide to write this post to record some highlights about Python. Furthermore, it is also a good way to do revision, especially for someone like me who rarely do revision.

##Syntax
range(a,b) returns the sequence of integers a, a + 1,..., b - 1

range(a,b,k): k is used as step value. For example:

for v in range(3,9,2):  
	print(v)  
...  
3  
5  
7

A function contains a header and body. The header begins with the def keyword, followed by the function’s name and parameters, and ends with a colon. For example:

def min(num1, num2):
	if num1 < num2:
		return num1
	else:
		return num2

Passing arguments by reference values. The reference value of each argument is passed to the parameter each time when we invoke a function with arguments. This is referred to as pass-by-value in programming terminology.

The contents of immutable objects cannot be changed. Whenever you assign a new number to a variable, Python creates a new object for the new number and assigns the reference of the new object to the variable. Notice that number and strings are known as immutable objects.

  • For arguments of immutable objects such as numbers and strings, the original value of the object outside the function is not changed

  • For arguments of mutable objects, the original value of the object is changed if the contents of the object are changed inside the function

Python return statement can return multiple values:

def sort(number1, number2):
if number1 < number2:
    return number1, number2
else:
    return number2,number1

n1,n2 = sort(453,23)
print("n1 is", n1)
print("n2 is", n2)

in and not in are used to test whether a string is in another string or not.

>>> s1 = "Welcome"
>>>"come" in s1
True
>>>"come" not in s1
False

The slicing operator returns a slice of the list using the syntax list[start : end].

The repr(s) function returns a raw string for s.

>>>s2 = "Hello \nWorld"
>>>print(s2)
Hello
World
>>>print(repr(s2))
'Hello \nWorld'

##Basic Data Structure

  • Tuple: use tuple for storing a fixed list of elements
  • Set: a set for storing and quickly accessing non-duplicate elements
  • Dictionary: store key/value pairs and access elements quickly using keys

For more samples, refer to https://github.com/wihoho/LearningPython