構造序列

1._len_(self)

2._getitem_(self,key)

3._setitem_(self,key,value)

4._delitem_(self,key)

程式演示：

myseq.py

class MySeq:

def __init__(self):

self.lseq = ["I","II","III","IV"]

def __len__(self):

return len(self.lseq)

def __getitem__(self,key):

if 0

return self.lseq[key]

if __name__ == "__main__":

m = MySeq()

for i in range(4):

print(m[i])