1. I choose the latest version of Python interpreter
   
2. Start with the simplest Hello world

>>> print("Hello world!")
Hello world!
>>> 

1. Like the simplest calculator
   Needless to say, you can understand it at a glance.

>>> 2+6
8
>>> 2/6
0.3333333333333333
>>> 2//6
0
>>> 5*9
45
>>> 5.0/6
0.8333333333333334
>>> 2.0//6
0.0
>>> 6//2
3
>>> 6.0//2
3.0
>>> 6.0/2.4
2.5
>>> 6.0//2.4 # integer division, discarding decimal parts
2.0
>>> 6%3
0
>>> 3%6 # Remainder operation
3
>>> 

1. variable

>>> x = 9
>>> x*x
81
>>> 

1. Sentence

>>> print(5*5)
25

1. Get user input

>>> input("How old are you: ")                 
How old are you: 250
'250'
>>> 

1. function

>>> 2**3
8
>>> pow(2,3)
8
>>> -10
-10
>>> abs(-10)
10
>>> 

1. Modular

>>> import math
>>> math.floor(54.69)
54
>>> 

Here we put in a mathematical module math, which has many functions that can be accessed by using math.flooar().

>>> from math import sqrt
>>> sqrt(-1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: math domain error
>>> sqrt(100)
10.0
>>> 
>>> import cmath  # cmath module supports complex numbers
>>> cmath.sqrt(-1)
1j
>>> 

The above is interactive window programming. Of course, we can create. py files to write programs.

1. Create the file 1001_base.py

#!/usr/bin/env python
print("Hello world")

(base) [root@8f5e50928415 python_action]# python 1001_base.py 
Hello world

10 notes

Use single-line comments in Python#
Multi-line comment usage

# Annotated content

'''
Annotated content
'''

"""
Annotated content
"""

1. Character string
   Processing strings in Python is as comfortable as dealing with English.

>>> x = 'Ni shi'       
>>> y = 'zhu ma?'
>>> 
>>> x + y 
'Ni shizhu ma?'
>>> y = ' zhu ma?'
>>> x + y         
'Ni shi zhu ma?'
>>> 

Very convenient stitching.

The most basic is finished.