如果数字介于两个值之间，则返回 [Python]
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Return if a number is between two values [Python]
提问by Tanishq dubey
Quite a simple question, but I have no clue on how to implement this.
相当简单的问题，但我不知道如何实现这一点。
Essentially:
本质上：
>>> r = range(4,-1)
>>> 3 in r
False
>>> q = range(-1,4)
>>> 3 in q
True
As you can see, I have the same bounds, -1 and 4, and the same test value, so how do I say that '3' is between'-1' and '4' when I do not know the order that they are given to me in?
如您所见，我有相同的边界，-1 和 4，以及相同的测试值，所以当我不知道它们的顺序时，我怎么说 '3' 是介于 '-1' 和 '4' 之间都给我了？
采纳答案by John La Rooy
Why not sort the bounds first?
为什么不先对边界进行排序？
r = range(*sorted((4, -1)))
q = range(*sorted((-1, 4)))
回答by 101
rangedoesn't do what you think it does.
range不会做你认为它会做的事情。
It creates a list; it's not a numeric range. Actually it does in Python 3.
它创建一个列表；它不是一个数字范围。实际上它在 Python 3 中确实如此。
Just imagine a case, when the lowerEndis -20000 and the upperEndis +20000. Using the range( -20000, 20000 )and comparing numin such a range()is a waste of both memory and CPU-power.
想象一个情况，当lowerEnd是 -20000 和upperEnd是 +20000 时。在这种情况下使用range( -20000, 20000 )和 比较会浪费内存和 CPU 能力。numrange()
It is quite enough to compare a numagainst lowerEnd& upperEndlimit
比较一个num对lowerEnd和upperEnd限制就足够了
You want to check:
您要检查：
num = 3
print(-1 < num < 4)
回答by d-coder
Why don't you try printing each step of your code snippet ? The code becomes self-explanatory to an extent. range()returns a list actually. So when this line is executed
为什么不尝试打印代码片段的每个步骤？代码在某种程度上变得一目了然。range()实际上返回一个列表。所以当这一行被执行时
r = range(4,-1)
print r
[] ## returned an empty list so which is why 3 in r returns False.
But when you execute like this
但是当你这样执行时
q = range(-1,4)
print q
[-1, 0, 1, 2, 3] ## Returned a list with 3 in it so 3 in q returns True
Now you want to check falls in range then you can do like this
现在你想检查范围内的落差，那么你可以这样做
if -1<= 3 <= 4:
print "Falls in the range"
else:
print "not in range"
output:
输出：
Falls in the range
回答by Ravdeep
Use a if statement to find the order
使用 if 语句查找订单
if c > d:
c, d = d, c
r = range(c, d)
回答by TinnyT
Maybe this?
也许这个？
r = list(xrange(4,-1,-1))
3 in r
True
q = list(xrange(-1,4,1))
3 in q
True
回答by gboffi
The syntax of the rangebuiltin needs a little while to be grasped but when working with the interactive interpreter help(range)is always a helping hand...
range内置语法需要一点时间来掌握，但在使用交互式解释help(range)器时总是有帮助的......
Python 2.x
蟒蛇 2.x
>>> print range(4,-1)
>>> print range(-1,4)
Pyton 3.x
派顿 3.x
>>> print(list(range(4,-1)))
>>> print(list(range(-1,4)))
but there is a problem (perhaps not with your specific issue) even if you add a step argument to the invocation of range (example for Python 2.x)
但是即使您向 range 的调用添加了 step 参数（例如 Python 2.x），也存在问题（可能不是您的特定问题）
>>> print range(4, -1, -1)
>>> print range(-1,4)
as you can see, the two ranges are not the same: the startargument is in the list, the stopone is not.
如您所见，这两个范围并不相同：start参数在列表中，stop一个不在列表中。
You can think of it in these terms: "in a range, the stopargument means stop before".
你可以用这些术语来考虑它：“在 a 中range，stop参数意味着在之前停止”。
回答by Bill O
As answered by 101 and d-coder, your question to find a value betweentwo other values should be constructed using <or <=operators, depending on what you want. Assuming that you know that r is a simple collection, like a list or tuple or range, but you don't know it's ordering, you could write:
正如 101 和 d-coder 所回答的那样，您在两个其他值之间找到一个值的问题应该使用<或<=运算符来构造 ，具体取决于您想要什么。假设您知道 r 是一个简单的集合，如列表或元组或范围，但您不知道它的排序，您可以编写：
>>> r = (-1,4,2,3,0)
>>> min(r) < 3 < max(r)
True
>>> min(r) < 2.5 < max(r)
True
The inoperator on the other hand will test whether your value is one of the values in the list
in另一方面，运算符将测试您的值是否是列表中的值之一
>>> 3 in r
True
>>> 2.5 in r
False
Finally, your first example failed because you did not specify a negative step when trying to define 'r' as a decreasing sequence. Here's an example where I'll specify a step size of -2 as the 3rd argument of range():
最后，您的第一个示例失败了，因为您在尝试将 'r' 定义为递减序列时没有指定负步骤。这是一个示例，我将指定步长为 -2 作为 的第三个参数range()：
>>> a = range(4,-1)
>>> print a
[]
>>> b = range(5,-1,-2)
>>> print b
[5, 3, 1]
>>> 3 in a
False
>>> 3 in b
True
