Linux：python控制语句（if条件语句、while语循环句和退出值）

一·if语句

# _*_ coding:utf-8 _*_
"""
file: if语句.py
date: 2018-07-17 20:48
author: jiong
desc:


"""
# 1.判断年龄是否为18周岁
age = 20
# 2.如果满18周岁,可以进入网吧
if age >=18:
    print '可以进入网吧'
# 3.如果不满18周岁,拒绝进入网吧
else:
    print '拒绝进入网吧'

二·逻辑运算

# _*_ coding:utf-8 _*_
"""
file: 逻辑运算.py
date: 2018-07-17 20:54
author: jiong
desc:


"""
# 1.一个整数变量,要求身高在160-170之间
height = 165
if height > 160 and height < 170:
    print '身高相符'
else:
    print '身高不符'

# 2.两个整数变量,只要求一门成绩>60,即为及格
score1 = 20
score2 = 8
if score1 > 60 or score2 > 60:
    print '考试及格'
else:
    print '考试不及格'

# 3.判断小明是否是男生
gender = False
if not gender:
    print '小明为男生'

# 3.判断小明是否是男生
gender = True
if  gender:
    print '小明为男生'

三·if嵌套

# _*_ coding:utf-8 _*_
"""
file: if嵌套.py
date: 2018-07-17 20:59
author: jiong
desc:


"""
# 定义布尔型变量has_ticket表示是否有车票
has_ticket = True
# 定义刀的长度
knife_length = 4
# 是否有车票.若有,允许进入
if has_ticket:
    print '请进入'
# 判断刀的长度
    if knife_length > 5:
        print '长度超过限定长度,不允许进入'
    else:
        print '长度未超过限定长度，允许进入'
else:
    print '请先购买车票'

四·if综合案例（以色子为例）

# _*_ coding:utf-8 _*_
"""
file: if案例_色子.py
date: 2018-07-17 21:02
author: jiong
desc:


"""

import random
# 1.从控制台输入筛子：1,2,3,4,5,6
player = int(raw_input('请输入筛子数：'))
# 2.电脑输出筛子数：1,2,3,4,5,6
computer = random.randint(1,6)
print  '玩家输入的是 %d 电脑输入的是 %d' % (player,computer)
# 3.判断
if (( player == 6 and computer <= 5 ) or
    ( player == 5 and computer <= 4 ) or
    ( player == 4 and computer <= 3 ) or
    ( player == 3 and computer <= 2 ) or
    ( player == 2 and computer <= 1 )):
    print '玩家胜利'
elif player == computer:
    print '平局'
else:
    print '电脑胜利'

五·while语句

1、简单while语句

# _*_ coding:utf-8 _*_
"""
file: while_1.py
date: 2018-07-17 21:04
author: jiong
desc:


"""
# 定义一个整数变量，记录循环的次数
i = 0
# 开始循环
while i<= 3:
    # 希望在循环内执行的代码
    print 'hello python'
    # 处理循环计数
    i += 1
print  '循环结束,i = %d' % i

2、计算0～100之间数字的求和

# _*_ coding:utf-8 _*_
"""
file: while_2.py
date: 2018-07-17 21:10
author: jiong
desc:


"""
# 计算0～100之间数字的求和
i = 0
result = 0
while i <= 100:
    print i
    result += i
    i += 1
print '0~100之间的数字求和的结果是： %d' % result

3、计算0～100之间奇数的和

# _*_ coding:utf-8 _*_
"""
file: while_3.py
date: 2018-07-17 21:11
author: jiong
desc:


"""
# 计算0～100之间奇数的和
i = 1
result = 0
while i <= 100:
    print i
    result += i
    i += 2
print '0~100之间奇数的和结果是： %d' % result

4、运行结果为2-3+4-5+6-7+8…+100

# _*_ coding:utf-8 _*_
"""
file: while_4.py
date: 2018-07-17 21:14
author: jiong
desc:


"""
i = 2
b = 0
while i <= 100:
    if i % 2 == 0:
        b = b + i
    else:
        b = b - i
    i += 1
print b

六·退出值

1、break

# _*_ coding:utf-8 _*_
"""
file: 退出值_break.py
date: 2018-07-17 21:16
author: jiong
desc:


"""
i = 0
while i < 10:
    if i == 3:
        # 满足某一条件时,退出循环,不再执行后续的重复的代码
        break
    print i
    i += 1
print 'over'

2、continue

# _*_ coding:utf-8 _*_
"""
file: 退出值_continue.py
date: 2018-07-17 21:18
author: jiong
desc:


"""
i = 0
while i <10:
    i += 1                       
    if i == 3:
        # 满足某一条件时
        # 不执行后续重复的代码
        # 其他条件的时候都要执行
        continue
    print i

七·while嵌套

1、显示出以下形式

*
* *
* * *
* * * *
* * * * *

方法一：

# _*_ coding:utf-8 _*_
"""
file: while嵌套.py
date: 2018-07-17 21:22
author: jiong
desc:


"""
"""
*
* *
* * *
* * * *
* * * * *
"""
row = 1
while row <= 5:
    print '* '   * row
    row += 1

方法二：

row = 1
while row <=5:
    col = 1
    while col <= row:
        col += 1
        print '*',
    #print '第 %d 行' %row
    print ''
    row += 1

2、嵌套循环（九九乘法表）

# _*_ coding:utf-8 _*_
"""
file: 嵌套循环_九九乘法表.py
date: 2018-07-17 21:29
author: jiong
desc:


"""
row = 1
while row <= 9:
    col = 1
    while col <= row:
        print '%d * %d = %d\t' % (row ,col,col * row),
        col += 1
    print ''
    row += 1

转移字符

\t：在控制台输入一个制表符,协助在输出文本的时候垂直方向保持对其
\n：换行符