7.31 PY formatted output Foundations and basic operators

7.31 PY formatted output Foundations and basic operators

Three ways formatted output

effect

The information entered by the user into a fixed format printing, due to the change of python version, there is a different formatted output, there is no practical effect, but can be more convenient to print out the result, more flowers in Hu show.

Placeholder

Placeholder with% s,% pass in variable names with characters you want to output.

.format format

{With} placeholder, with .format traditional values, Hu spent in the show, no practical effect.

f-String formatting

py3.6 unique version, format with print (f '{} {} {}'), simple to use and show flowers in HU. And you can customize an integer of decimal places, print (f '{s: .2f}')

use

For example: output format output in three ways: "My name is Wangzhi Hui, my height is 185, my weight is 110"

name = '汪智慧'
height = 185
weight = 110
print('My name is %s , my height is %s,my weight is %s' 
      %(name,height,weight)) # %s表示匹配所有字符
print("My name is {}, my height is {}, my weight is {}" .format(name,height,weight))
print(f'My name is {name}, my height is {height}, my weight is {weight}')

Basic operators

Arithmetic Operators

Arithmetic operators grabbed what we started from the primary school arithmetic, too simple, not to show ......

  + - * / % ** // (%取余，**幂，//整除)

Comparison Operators

Two conditions are compared, the Boolean value T / F

 == != <> > <  >=  <= (!=与<>类似，都是表示不等于)

print('a' == 'abc') # False
print('a' != 'abc') # True
print( 1+1 == 2 ) # True

Assignment Operators

Value is about the value assigned to the variable, including monohydric and dihydric assignment operator assignment operator

Mono: i.e., arithmetic operators + - * /% // ** (% Remainder ** power, divisible //)

Two yuan: + = - = = * / ** =% = = = //

a += b # a=a+b
a %= b # a=a%b
a **= b # a=a**b
a //= b # a=a//b

Logical Operators

I.e. symbolic logic operations, Boolean operation to give

​ and or not

3 > 3 and 1 > 2 or 2 > 1  # False

Identity operator

Identity operator used to compare two of the memory cells.

and is the difference between ==: is configured to determine whether two variables refer to the same objects (whether in the same memory space), a reference value for determining == variables are equal.

x = 257
y = x
z = 257

print(f'x is y:{x is y}') # x is y:True
print(f'x == y:{x == y}') # x == y:True
print(f'x is z:{x is z}') # x is z:False
print(f'x == z:{x == z}') # x == z:True

Extended: python operator in priority

python operator precedence in mathematics equivalent of the first count and then count addition and subtraction multiplication and division, in fact, not necessary, your high priority brackets on the line ...