# 第5讲 python 中判断循环语句
# 1、python中if 判断语句
# 1)if单分支条件判断语句
# name = input('请输入您的用户名:')
# if name =='admin':
# print('管理员')
# else:
# print('普通用户')
#
# num = 5
# if num >5:
# print('美女')
# else:
# print('帅哥')
# 2)if 条件判断语句多分支
# name = input('请输入您的用户名:')
# if name =='admin':
# print('高富帅')
# elif name =='xiaoduan':
# print('穷人')
# elif name =='xiaozhang':
# print('美女')
# else:
# print('帅哥')
# 3)if 条件判断单分支 三目运算
# name = input('请输入您的用户名:')
# print('南京') if name =='xiaoduan'else print('深圳')
# 上面的写法等同于以下
# name = input('请输入您的用户名:')
# if name =='admin':
# print('南京')
# else:
# print('深圳')
#
# dict1 = {'name':'xiaoduan','age':18}
# if dict1.__contains__('class') is True:
# print(dict1)
# else:
# dict1['class'] = 1833
# dict1.setdefault('class',1833)
# print(dict1) #{'name': 'xiaoduan', 'age': 18, 'class': 1833}
# 练习题:把上面的判断语句转化为三目运算
# dict1 = {'name':'xiaoduan','age':18}
# print(dict1) if dict1.__contains__('class') is True else dict1.setdefault('class',1833) and print(dict1)
# 4) if 语句之if嵌套语句
# if 判断
# 执行
# if 判断
# 执行
# else:
# 执行
# else:
# 执行
# 登录功能实战练习: 通
# 过输入函数输入用户名、先判断用户名是否正确、用户名正确则 进行密码的判断如果用户名错误则提示
# :用户错误、请重新输入、密码错误则提 示:您输入的密码有误、请重新输入密码输入正确则登录成功
#name = 'admin'
#pwd = '123456'
# name = input('请输入您的账号:')
# if name =='admin':
# pwd = input('请输入您的密码:')
# if pwd =='123456':
# print('登录成功')
# else:
# print('您输入的密码有误、请重新输入密码输入正确则登录成功')
# else:
# print('用户错误、请重新输入')
#
# dict1 = {'name':'admin','pwd':'123456'}
# name = input('请输入您的账号:')
# if name ==dict1.get('name'):
# pwd = input('请输入您的密码:')
# if pwd ==dict1.get(pwd):
# print('登录成功')
# else:
# print('您输入的密码有误、请重新输入密码输入正确则登录成功')
# else:
# print('用户错误、请重新输入')
# 2、while 循环语句
# while 条件表达式:
# 循环体语句
# while什么时候进入循环?当循环条件成立时,
# 进入循环 while什么时候退出循环?当循环条件不成立时,退出循环
# 注意:在写while循环语句时一定要让循环条件发生变化,否认很容易陷入死循环中
# num = 1
# while num <=5:
# print('这是第%d的次循环'%(num))
# num =num +1
# 根据while 循环 求出1-100的和 1+2+3+4...
# i = 1
# j = 0 #求和变量
# while i <=100:
# j = j+i #这里每次循环相加
# i = i+1 #满足条件是跳出循环
# print(j) #打印每次循环的和
# print(j) #5050 打印最终的和
# i = 1 j =1
# i = 2 j = 3
# i = 3 j = 6
# 作业:根据 while 循环求出奇数之和1-100
# i = 1
# j = 0 #求和变量
# while i <=100:
# j = j+i #这里每次循环相加
# i = i+2 #满足条件是跳出循环
# #print(j) #打印每次循环的和
# print(j) #2500 # 打印最终的和
#根据 while 循环求出偶数之和1-100 2+4+6+8
# i = 2 #或者0
# j = 0 #求和变量
# while i <=100:
# j = j+i #这里每次循环相加
# i = i+2 #满足条件是跳出循环
# print(j) #打印每次循环的和
# print(j) #2550 # 打印最终的和
#根据while 循环求1-100 之内奇数和偶数之差
# i = 0
# odd = 0 #奇数之和
# even = 0 #偶数之和
# while i <=100:
# if i % 2==0: #偶数值
# even = even +i
# else: #奇数值
# odd = odd +i
# i= i+1
# print(even - odd) #50
# 5、for 循环语句
# 1)for 循环和range 函数 结合使用,for 后面加一个冒号
# for i in range(10):
# # print(i) #竖着打印0-9
# print(i,end="") #0123456789 #取不到10
# #
# for i in range(0,10):
# print(i) #竖着打印0-9
#
# for i in range(0,10,1):
# print(i) #竖着打印0-9 挨个取 有点像切片
#
# for i in range(0,10,2):
# print(i) #打印的结果0 2 4 6 8 隔一个取一个
#
# for i in range(10,0):
# print(i) #打印为空
#
# for i in range(10,0,-1):
# print(i) #打印结果10-1 0取不到,数字倒过来显示
#
# for i in range(10,0,-2):
# print(i) #打印结果10 8 6 4 2
# 2)for 循环语句的示例
# ① 求1-100之和
# sum = 0
# for i in range(1,101):
# sum = sum +i
# print(sum) #5050
# ② 求1-100 奇数之和
# sum = 0
# for i in range(1,101,2):
# sum = sum+i
# print(sum) #2500
# ③ 求1-100 偶数之和
# sum = 0
# for i in range(0,101,2):
# sum = sum+i
# print(sum) #2550
# 3)for 循环遍历字符串 列表 字典 集合 元组
# ① 遍历字符串
# str1 = 'python'
# for i in str1:
# print(i,end='')
# ② 遍历列表
# list1 = [1,2,3,4]
# for i in list1:
# print(i)
# ③遍历集合
# set1 = {1,2,3,4,5}
# for i in set1:
# print(i)
# ④ 遍历元组
# tuple1 = (1,2,3,4)
# for i in tuple1:
# print(i)
# ⑤遍历字典
# dict1 = {'name':'xiaoduan','age':18}
# for i in dict1:
# print(i,dict1) #name xiaoduan age 18
# ⑥ 遍历整型 ==》不可以遍历整型
# test = 12345
# for i in test:
# print(i)
# 练习题:用for 循环打印出字符串duoceshi 每个字符以及每隔字符的索引值,并格式化输出
# str1 = 'duoceshi'
# for i in str1:
# # print('%s字符对应的索引值是%d'%(i,str1.index(i)))
# s = str1.index(i) #0-7
# print('%s字符对应的索引值是%d'%(i,s))
# 6、continue 语句
# 用法:continue语句用来告诉Python跳过当前循环的剩余语句,然后继续进 行下一轮循环。
# for i in range(10):
# if i ==6:
# continue #continue 是跳过i= 6 这个循环
# print(i,end='') #012345789
# 7、break 语句
# 用法:语句会立即退出循环,在其后边的循环代码不会被执行。
# for i in range(10):
# if i ==6:
# break #break 是当i= 6时终止循环
# print(i,end='') #012345
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