1. 字符串、元组和列表相互转化
s = 'abcdef'
li = ['a','b','c','d']
tu = (1,2,4,9)
v = tuple(s)
print('v = ',v)
w = list(s)
print('w =',w)
m = list(tu)
print('m =',m) ————————————————
v = ('a', 'b', 'c', 'd', 'e', 'f')
w = ['a', 'b', 'c', 'd', 'e', 'f']
m = [1, 2, 4, 9]
2. extend()
li = ['a','bcd']
li.extend((11,22,33))
print(li) ['a', 'bcd', 11, 22, 33]
3.如果元素中只有字符串，可以拼接转换u = ''.join(li)
print('u =',u)
u = abcd