# coding=utf-8
l1=list('joy')
print(l1)
l1.append(' ')
print('尾部添加空白字符：')
print(l1)
l1.extend('singing')
print('尾部添加字符串：')
print(l1)
l1[:0]='I e'
print('在首部添加字符串：')
print(l1)
l1.insert(3,'n')
print('在索引3的位置插入：')
print(l1)
print('n在l1中出现的次数：')
print(l1.count('n'))
print('n在l1中首次出现的位置：')
print(l1.index('n'))
l2=[ord(i) for i in l1]
l3=[ord(i) for i in l1]
l22=l2[0:7]
l22.sort(key=lambda i:len(str(i)),reverse=False)
print('升序排列')
print(l22)
l222=l2[8:]
l222.sort(key=lambda i:len(str(i)),reverse=True)
print('降序排列')
print(l222)
l2=l22+l222
print('l1中奇数位元素')
print(l1[::2])
l11=l1[::2]
l11.reverse()
print('逆序排列l1中的奇数位元素')
print(l11)
l1[0]='Y'
print('将I替换成Y')
print(l1)
l1[8:12]='danc'
print('用danc代替sing')
print(l1)
l2.pop()
l2.pop(0)
print('删除首部和尾部的l2')
print(l2)
l2=l2[0::2]
del l2
