初识逻辑与if语句

逻辑判断与逻辑语句

  • 对于一件事情正确与否(真假的判断)
  • 根据判断的结果做不同的事情 , 就是我们的逻辑业务
  • 对于条件满足的判断语句 , 就是条件语句

一个逻辑语句是由条件语句和业务语句组合而成的

if语句

功能
  • 判断一个命题的真实性 , 如果命题为真(True)则执行if的逻辑语句
用法
  • if bool_result : # 语法块
  • ​ do # 业务代码块 注意缩进
    • 缩进是由一个TAB或者四个空格组成的
  • in and
返回值
  • if 属于关键字 , 没有返回值

代码

# coding:utf-8
info = 'my name is xiaomu'
info_list = info.split()
print(info_list)
if info_list[0] == 'xiaomu':
print(1)
info_list[0] = 'dewei'
if info_list[1] == 'xiaomu':
print(2)
info_list[1] = 'dewei'
if info_list[2] == 'xiaomu':
print(3)
info_list[2] = 'dewei'
if info_list[-1] == 'xiaomu':
print(4)
info_list[-1] = 'dewei'
print(info_list)
info = ' '.join(info_list)
print(info)
info = 'my name is dewei, i am a pythoner, i love python'
info_list = info.split()
if info_list[0] in ['python', 'i']:
info_list[0] = '*'
if info_list[1] == 'python' or info_list[1] == 'i':
info_list[1] = '*'
if info_list[2] == 'python' or info_list[2] == 'i':
info_list[2] = '*'
if info_list[3] == 'python' or info_list[3] == 'i':
info_list[3] = '*'
if info_list[4] == 'python' or info_list[4] == 'i':
info_list[4] = '*'
if info_list[5] == 'python' or info_list[5] == 'i':
info_list[5] = '*'
if info_list[6] == 'python' or info_list[6] == 'i':
info_list[6] = '*'
if info_list[7] == 'python' or info_list[7] == 'i':
info_list[7] = '*'
if info_list[8] == 'python' or info_list[8] == 'i':
info_list[8] = '*'
if info_list[9] == 'python' or info_list[9] == 'i':
info_list[9] = '*'
if info_list[-1] in ['python', 'i']:
info_list[10] = '*'
print(info_list)
info = ' '.join(info_list)
print(info)
info = 'my name is dewei'
print(len(info))
if len(info) > 10 and len(info) != 16:
print(info.replace('dewei', 'xiaomu'))
print('finish')
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