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Python基础2

1. if语句

1.1 功能

  if语句主要用来根据周围环境条件(即expession)的变化做出不同的反应(即执行代码)

1.2 语法

1.2.1 单分支结构

if单分支单条件:

if expression:

  expr_true_suite

注释:expession为真执行代码expr_true_suite

示例:

技术分享
name = test
input_name = input("input_name:")
if name == input_name :
    print("right!")
View Code

 

if单分支多条件:

if expression1 and expression2 :
#条件两边可用and 或or

    expr_true_suite
注释:expession为真执行代码expr_true_suite

示例:

技术分享
name = test
age = 22
input_name = input("input_name:")
input_age = int(input("input_age:") )
if name == input_name  and age == input_age :
    print("name and is right!")
View Code

 

if+else:

if expression:

    expr_true_suite   

else:

    expr_false_suite

示例:

技术分享
name = test
input_name = input("input_name:")
if name == input_name:
    print("name is right!")
else:
    print("name is error")
View Code

 

1.2.2 多分支结构

if多分支结构:

if expession1:

    expr1_true_suite

elif expression2:

    expr2_true_suite

elif expession3:

    expr3_true_suite

else:

    none_of_the_above_suite

示例:

技术分享
name = test
age = 22
input_name = input("input_name:")
input_age = int(input("input_age:") )
if name !=input_name and age !=input_age :
    print("name and age all error!")
elif name == input_name and age !=input_age :
    print("name right and age error")
elif name != input_name and age ==input_age :
    print("age right and name error")
else:
    print("all right")
View Code

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. while循环

在未到达设置的条件前(或没有限制条件)时,会一直执行。

猜年龄优化:

输入三次不对则退出

count = 0
self_age = 56
while count <3:
    guess_age = int(input("guess_age:"))
    # if guess_age.isdigit():
    #     guess_age == int(guess_age)
    # else:
    #     continue
    if guess_age == self_age:
        print("you are right!!!!")
        break
    elif guess_age < self_age:
        print("try bigger!!!")
    else:
        print("try small!!!!")
    count +=1

else:
    print("try too many is error ! byebye....")

 

Python基础2