x = [4, 6, 2, 1, 7, 9]
x.sort()
print (x) # [1, 2, 4, 6, 7, 9]

x = [4, 6, 2, 1, 7, 9]
y = x[:]
y.sort()
print(y) # [1, 2, 4, 6, 7, 9]
print(x) # [4, 6, 2, 1, 7, 9]

x =[4, 6, 2, 1, 7, 9]
y = sorted(x)
print (y) #[1, 2, 4, 6, 7, 9]
print (x) #[4, 6, 2, 1, 7, 9]

print (sorted('Python')) #['P', 'h', 'n', 'o', 't', 'y']

# 2.有一个list['This','is','a','Boy','!'],所有元素都是字符串，对它进行大小写无关的排序
li=['This','is','a','Boy','!']
l=[i.lower() for i in li]
# l1 =l[:]
l.sort() # 对原列表进行排序，无返回值
print(l)
# print(sorted(l1))  # 有返回值原列表没有变化
# print(l1)

x = ['mmm', 'mm', 'mm', 'm' ]
x.sort(key = len)
print (x) # ['m', 'mm', 'mm', 'mmm']

y = [3, 2, 8 ,0 , 1]
y.sort(reverse = True)
print (y) #[8, 3, 2, 1, 0]