摘要：
classmates = ['Michael','Bob','Tracy'] classmates.append('Rose') classmates.insert(1,'Jack') classmates.pop() classmates.pop(0) classmates[0] = 'Tom' print(classmates) ['Tom', 'Bob', 'Tracy'] 阅读全文
摘要：
fr = open('letter.txt.txt', mode='r', encoding='utf-8') plaincode = fr.read() print('明文:' + plaincode) print('密文:', end='') for c in plaincode: print(chr(ord(c)+3),end='') 明文:一小时后行动。 ... 阅读全文