1.variables must stary with a letter or underscore_

CASE sensitive!!

2. ** power

% remainder

/ 不是整数除法，就是正常的除 （in python 3） python2 和 c++一样还是整数除法

1+1.0 // 2.0 auto do the float convert for you

// --- Interger Division

5//3 #1

10//3 #3 (always round down)

1/2 #0.5 python always get float

2**3 #8

49**0.5 #7

13%2 #1

3. naming_conventions

most variables should be lower case,

CAPITAL_NAME usually is constants

UpperCamelCase : refer to a class

"dunder" for double underscore ***

4.string format

interpolate #插入

f-strings (python 3.6+)

x = 10

formatted = f"I told you {x} times!" #不可以忘了这个f！

#you can also do math in the {}

# in python 2 .format() --play ground only support it

print("the {} is ).format(sth)

first = "Colt"

last = "Steele"

formatted = "First Name: {}, Last Name: {}". format(first, last) #可以直接在string 后加

5.is vs ==

is check with the memory and == checks value

is--checking equality

a = 1

a == 1 #True

a is 1 #True

a = [1,2,3]

b = [1,2,3]

a == b #True

a is b #Flase, they are different objects

c = b

b is c #True, b and c are pointing to the same stuff

a = 13

b = 13

a == b #True

a is b #True

6. use # for comments in python

''' for python multiple line comments

7. python use indent to distinguish block, which is 4 spaces, it is better to use space than tab, to avoid difference between different editors

8. python 里的print（） 有自动换行功效

9. for installing package in jupyter

https://jakevdp.github.io/blog/2017/12/05/installing-python-packages-from-jupyter/