I learn python road - three days before the summary

1. Start Basics 1.1 first Python code

First create an arbitrary file, ending py format, then enter the code inside, run pycharm or Python shell inside

 

print ( "fishing to catch saury, saury fishing to the island")

 

1.2 interpreter encoding

ascii, 8 bits = 1 byte, a byte is a letter, Py2 default interpretation is encoded in ASCII.

Unicode, 32 bits = 4 bytes, called Unicode, a letter or characters are four bytes

utf-8, which is a compressed version of unicode, a byte is a letter, a character is three bytes, Py3 default interpreter code is utf-8

1.3 Output

print ( "Enter what you want to enter.")

1.4 Variable

Name of the variable letters, numbers, underscores, and can not start with a number, not a built-in Python keywords as variable names. Named variables known to do see name meaning, connections underlined link

1.4.1 Assignment of variables

x=1+2+3+4+5
y=x*5
z=y*7
print(z)

age1=18
age2=age1
age1=12
age3=age2
print(age1,age2,age3)

age=12
age=12+1
age1=age+1
print("我今年：",age1)
name1='alex'
name2=name1
name1='wusir'
name3=name2
print(name1,name2,name3)

num1=2
num2=3
print(num1+num2)

1.5 Notes

General single-line comments in a line beginning with #, multi-line comments in the first row on the line and last line of the next line plus "" "If you want multiple single-line comments while pycharm inside, then use the keyboard shortcut Ctrl +?

1.6 General Data Types

str is a string

1.6.1 string splicing

s1="a"
s2='bc'
print(s1+s2)

1.6.2 string multiplication

name = "I love to learn Python" 
Print (name * 8) 
# I love learning Pythonch repeated eight times