如何在Python中创建循环 [英] How to create a loop in Python
问题描述
这是我的代码:
my_Sentence = input('Enter your sentence. ')
sen_length = len(my_Sentence)
sen_len = int(sen_length)
while not (sen_len < 10 ):
if sen_len < 10:
print ('Good')
else:
print ('Wo thats to long')
break
我正在尝试使程序不断要求用户写一个句子,直到它少于10个字符.我需要知道如何再次使用该程序作为一个句子,但是我认为最简单的方法是使代码从头开始.但我不急于做到这一点.有人可以帮忙吗?
模式
反复提示用户输入的一般模式是:
# 1. Many valid responses, terminating when an invalid one is provided
while True:
user_response = get_user_input()
if test_that(user_response) is valid:
do_work_with(user_response)
else:
handle_invalid_response()
break
我们使用无限循环while True:
,而不是重复两次我们的get_user_input
函数(帽尖). /p>
如果要检查相反的情况,只需更改break
的位置:
# 2. Many invalid responses, terminating when a valid one is provided
while True:
user_response = get_user_input()
if test_that(user_response) is valid:
do_work_with(user_response)
break
else:
handle_invalid_response()
如果您需要循环工作,但在用户提供无效输入时向用户发出警告,则只需添加一个测试,即可检查某种quit
命令,并且仅在其中进行break
检查:
# 3. Handle both valid and invalid responses
while True:
user_response = get_user_input()
if test_that(user_response) is quit:
break
if test_that(user_response) is valid:
do_work_with(user_response)
else:
warn_user_about_invalid_response()
将模式匹配到您的具体情况
您要提示用户向您提供少于10个字符的句子.这是模式2的实例(许多无效响应,仅需要一个有效响应).将模式2映射到您的代码上,我们得到:
# Get user response
while True:
sentence = input("Please provide a sentence")
# Check for invalid states
if len(sentence) >= 10:
# Warn the user of the invalid state
print("Sentence must be under 10 characters, please try again")
else:
# Do the one-off work you need to do
print("Thank you for being succinct!")
break
This is my code:
my_Sentence = input('Enter your sentence. ')
sen_length = len(my_Sentence)
sen_len = int(sen_length)
while not (sen_len < 10 ):
if sen_len < 10:
print ('Good')
else:
print ('Wo thats to long')
break
I'm trying to make the program ask the user continuously to write a sentence, until it is under 10 characters. I need to know how to have the program as for a sentence again, but I think the simplest way would be to have the code start from the top; but I'm not surte how to do that. Can someone help?
The pattern
The general pattern for repeatedly prompting for user input is:
# 1. Many valid responses, terminating when an invalid one is provided
while True:
user_response = get_user_input()
if test_that(user_response) is valid:
do_work_with(user_response)
else:
handle_invalid_response()
break
We use the infinite loop while True:
rather than repeating our get_user_input
function twice (hat tip).
If you want to check the opposite case, you simply change the location of the break
:
# 2. Many invalid responses, terminating when a valid one is provided
while True:
user_response = get_user_input()
if test_that(user_response) is valid:
do_work_with(user_response)
break
else:
handle_invalid_response()
If you need to do work in a loop but warn the user when they provide invalid input then you just need to add a test that checks for a quit
command of some kind and only break
there:
# 3. Handle both valid and invalid responses
while True:
user_response = get_user_input()
if test_that(user_response) is quit:
break
if test_that(user_response) is valid:
do_work_with(user_response)
else:
warn_user_about_invalid_response()
Mapping the pattern to your specific case
You want to prompt a user to provide you a less-than-ten-character sentence. This is an instance of pattern #2 (many invalid responses, only one valid response required). Mapping pattern #2 onto your code we get:
# Get user response
while True:
sentence = input("Please provide a sentence")
# Check for invalid states
if len(sentence) >= 10:
# Warn the user of the invalid state
print("Sentence must be under 10 characters, please try again")
else:
# Do the one-off work you need to do
print("Thank you for being succinct!")
break
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