Various expressions
A ternary expression
For chestnuts to clear out
name = 'jiayi'
if name == 'jiayi'
print('hahaha')
else:
print('xixixi')
===========================================================
print('hahaha') if name == 'jiayi' else print('xixixi')
#上下两个代码的性质是一样的，这就是三元表达式A triplet of expressions only supports dual-branch structure
Second, the list comprehension of formula
For chestnuts to clear out
lt = [0,1,2,3,4]
lt = []
for i in range(10):
lt.append(i**2)
print(lt)
==========================================================
lt = [i for i in range(10)]
print(lt)
#上下两个代码的性质是一样的，这就是列表推导式
#而且lt = [i for i in range(10)]的第一个i可以进行算数运算，比如：lt = [i ** 2 for i in range(10)]Third, the Dictionary of formula
For chestnuts to clear out
z = zip(['a','b','c','d'],[1,2,3,4])
for k,v in z:
print(k,v)
# 字典生成式一般与zip(拉链函数--》列表里面包了元组)连用
dic = {k:v**2 for k,v in zip(['a','b','c','d'],[1,2,3,4])} #压缩方法，Python解释器的内置方法
print(dic)
------------------------------------------------------------
b 2
c 3
d 4
{'a': 1, 'b': 4, 'c': 9, 'd': 16}