Question

好吧，我刚刚开始学习python，并且不知道在哪里提出这个问题。我写了这个计算器并且有效。

a,b=input("Enter two numbers (sperated by a comma): ")
operator=raw_input("Do you want to add, subtract, multiply, or divide? ")
if operator=="divide":
    print "Your answer is", a / b
if operator=="multiply":
    print "Your answer is", a * b
if operator=="add":
    print "Your answer is", a + b
if operator=="subtract":
    print "Your answer is", a - b    
repeat=raw_input("Do you want to perform another calculation(yes or no)? ")

现在，我想知道如果输入是肯定的，如何重新启动这个程序。我搜索了一个答案，但我无法弄清楚循环整个事情的命令。就像在while循环中一样，你必须在条件之后给出一个命令但是那个命令是什么？ p hal。

Answer 1

将其包裹在while循环中：

repeat = "yes"
while repeat.lower().strip() == 'yes':
    a,b=input("Enter two numbers (sperated by a comma): ")
    operator=raw_input("Do you want to add, subtract, multiply, or divide? ")
    if operator=="divide":
        print "Your answer is", a / b
    if operator=="multiply":
        print "Your answer is", a * b
    if operator=="add":
        print "Your answer is", a + b
    if operator=="subtract":
        print "Your answer is", a - b    
    repeat=raw_input("Do you want to perform another calculation(yes or no)? ")

只要答案为“是”（不区分大小写），这将循环。最初的'重复'是为了保证循环运行至少一次。

顺便说一句，您可以将if测试转换成字典：

import operator
ops = {'divide': operator.div,
       'multiply': operator.mul,
       'add': operator.add,
       'subtract': operator.sub}
repeat = "yes"
while repeat.lower().strip() == 'yes':
    a,b=input("Enter two numbers (sperated by a comma): ")
    operator=raw_input("Do you want to add, subtract, multiply, or divide? ").lower().strip()
    if operator not in ops:
        print 'Invalid operator:', operator
        continue
    print "Your answer is", ops[operator](a,b)
    repeat=raw_input("Do you want to perform another calculation(yes or no)? ")

Answer 2

while True:
    a,b=input("Enter two numbers (sperated by a comma): ")
    operator=raw_input("Do you want to add, subtract, multiply, or divide? ")
    if operator=="divide":
        print "Your answer is", a / b
    if operator=="multiply":
        print "Your answer is", a * b
    if operator=="add":
        print "Your answer is", a + b
    if operator=="subtract":
        print "Your answer is", a - b    
    repeat=raw_input("Do you want to perform another calculation(yes or no)? ")
    if repeat == 'no':
        break

虽然True会继续循环，但它可以被关键字break打破（它会突破最近的循环（for或while））。

当处理来自用户的输入以确定条件时，最好检查来自用户的输入是否以＆＃34; y＆＃34; （是）或以＆＃34; n＆＃34;开头（不），因为用户可能输入y而不是yes并且他可能会弄乱大写，这里有一个实现这个的代码：

while True:
    a,b=input("Enter two numbers (sperated by a comma): ")
    operator=raw_input("Do you want to add, subtract, multiply, or divide? ")
    if operator=="divide":
        print "Your answer is", a / b
    if operator=="multiply":
        print "Your answer is", a * b
    if operator=="add":
        print "Your answer is", a + b
    if operator=="subtract":
        print "Your answer is", a - b    
    repeat=raw_input("Do you want to perform another calculation(yes or no)? ")
    if repeat.lower.startswith('n'):
        break

＆＃34;重复＆＃34;是一个字符串，它有一个名为＆＃34; lower＆＃34;的方法（类似于函数），此方法返回字符串的小写表示，然后您可以检查该小写表示（也是一个字符串）是否以信＆＃34; n＆＃34;通过使用另一个名为startswith的方法。

Answer 3

Try this

You can use while True: with this the code written inside the for loop 
will execute infinitely,
To stop execution you can use Ctrl + C 

while True:
    a,b=input("Enter two numbers (sperated by a comma): ")
    operator=raw_input("Do you want to add, subtract, multiply, or divide? ")
    if operator=="divide":
        print "Your answer is", a / b
    if operator=="multiply":
        print "Your answer is", a * b
    if operator=="add":
        print "Your answer is", a + b
    if operator=="subtract":
        print "Your answer is", a - b    
    repeat=raw_input("Do you want to perform another calculation(yes or no)? ")
    if repeat == "no":
        break

Answer 4

试试这个：

while True:    
    a,b=input("Enter two numbers (sperated by a comma): ")
    operator=raw_input("Do you want to add, subtract, multiply, or divide? ")
    if operator=="divide":
        print "Your answer is", a / b
    if operator=="multiply":
        print "Your answer is", a * b
    if operator=="add":
        print "Your answer is", a + b
    if operator=="subtract":
        print "Your answer is", a - b    
    repeat=raw_input("Do you want to perform another calculation(yes or no)? ")
    if repeat == "no":
        break

Answer 5

        while True:                
            try:
                #I want this bit here to fire without waiting for the client to send anything
                #right now it works except the client has to send a character first
                #check for stuff to send back
                for fname in os.listdir('data/%s/in' % dirname):  
                    print(fname)
                    f = open('data/%s/in/%s' % (dirname, fname), "r")
                    client.send(f.readline()) 
                        
                data = client.recv(size)
                if data:
                    
                    bucket=bucket+data
                      
                else:
                    raise error('Client disconnected')
                    
                
            except Exception as e:
                client.close()
                print(e)
                return False

它会一直循环直到特定条件成立

我如何在python中无限循环这个程序？

5 个答案: