如何使用用户输入结束程序?

本文介绍了如何使用用户输入结束程序?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我是python的新手，我正在编写一个将毫米转换为英寸的程序.基本上，它是一个连续循环，可让您不断输入数字并获得正确的转换后的测量值.我想放置一个IF语句，该语句将允许用户键入"end"以结束程序，而不是转换更多的度量单位.我将如何进行这项工作(什么python代码可以让您退出书面程序并可以在IF语句中使用?)?

convert=float(25.4) while True: print("*******MM*******") MM=float(input()) Results=float(MM/convert) print("*****Inches*****") print("%.3f" % Results) print("%.4f" % Results) print("%.5f" % Results)

解决方案

只需使用 iter 和前哨:

print ("Convert MM to Inches") convert=float(25.4) for i in iter(input, 'end'): print("*******MM*******") try: MM=float(i) except ValueError: print("can't convert {}".format(i)) else: Results=float(MM/convert) print("*****Inches*****") print("%.3f" % Results) print("%.4f" % Results) print("%.5f" % Results)

通过这种方式， iter 调用 input 并将其返回值存储在i中，直到i == 'end'. /p>

请注意，如上例所示，如果用户输入非数字值，您可能需要进行一些错误检查.

I'm new to python and I am writing a program that converts Millimeters to Inches. Basically its a continuous loop that allows you to keep putting in numbers and get the correct converted measurement. I want to put an IF statement that will allow the user to type "end" to end the program instead of converting more units of measurement. How would I go about making this work (what python code allows you to exit a written program and can be used in an IF statement.)?

convert=float(25.4) while True: print("*******MM*******") MM=float(input()) Results=float(MM/convert) print("*****Inches*****") print("%.3f" % Results) print("%.4f" % Results) print("%.5f" % Results)

解决方案

Just use iter with a sentinel:

print ("Convert MM to Inches") convert=float(25.4) for i in iter(input, 'end'): print("*******MM*******") try: MM=float(i) except ValueError: print("can't convert {}".format(i)) else: Results=float(MM/convert) print("*****Inches*****") print("%.3f" % Results) print("%.4f" % Results) print("%.5f" % Results)

This way, iter calls input and stores the return value of it in i until i == 'end'.

Note that you probably want some error checking in case the user enters a non numeric value like in the example above.