如何在带有 range() 的循环中使用变量？（Python）
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How do I use variables in a loop with range()? (Python)
提问by jakerm2002
I've been searching for quite a while, and I can't seem to find the answer to this. I want to know if you can use variables when using the range() function. For example, I can't get this to work:
我一直在寻找很长一段时间，我似乎无法找到这个问题的答案。我想知道在使用range()函数时是否可以使用变量。例如，我无法让它工作：
l=raw_input('Enter Length.')
#Let's say I enter 9.
l=9
for i in range (0,l):
#Do something (like append to a list)
Python tells me I cannot use variables when using the range function. Can anybody help me?
Python 告诉我在使用 range 函数时不能使用变量。有谁能够帮助我？
采纳答案by ranendra
Since the user inputs is a stringand you need integervalues to define the range, you can typecast the input to be a integer value using intmethod.
由于用户输入是一个字符串并且您需要整数值来定义范围，因此您可以使用int方法将输入类型转换为整数值。
>> l=int(raw_input('Enter Length: ')) # python 3: int(input('Enter Length: '))
>> for i in range (0,l):
>> #Do something (like append to a list)
回答by Stanislav Teroff
You ask user to input a number
你要求用户输入一个数字
l = raw_input('Enter Length: ')
But the problem is that entered number will be presented as a stringinstead of int. So you have to convert string 2 int
但问题是输入的数字将显示为字符串而不是 int。所以你必须转换字符串 2 int
l = int(raw_input('Enter Length: '))
If you use Python 2.X you also can optimize your code - instead of range you might use xrange. It works much faster.
如果您使用 Python 2.X，您还可以优化您的代码 - 您可以使用xrange代替 range 。它的工作速度要快得多。
for i in xrange (l):
#Do something (like append to a list)
In Python 3.X xrange was implemented by default
在 Python 3.X xrange 是默认实现的
回答by Luis Manuel Sánchez Ubiera
Try this code:
试试这个代码：
x = int(input("the number you want"))
for i in range(x):
