CumSum 直到达到某个值然后停止并打印 'MAX'

Question

我有数字列表 (0-100)

numbers = list(range(101))

然后我需要计算 CumSum 直到达到 1000 然后停止计算并打印 'max is reached'

np.cumsum(numbers)

array([   0,    1,    3,    6,   10,   15,   21,   28,   36,   45,   55,
     66,   78,   91,  105,  120,  136,  153,  171,  190,  210,  231,
    253,  276,  300,  325,  351,  378,  406,  435,  465,  496,  528,
    561,  595,  630,  666,  703,  741,  780,  820,  861,  903,  946,
    990, 1035, 1081, 1128, 1176, 1225, 1275, 1326, 1378, 1431, 1485,
   1540, 1596, 1653, 1711, 1770, 1830, 1891, 1953, 2016, 2080, 2145,
   2211, 2278, 2346, 2415, 2485, 2556, 2628, 2701, 2775, 2850, 2926,
   3003, 3081, 3160, 3240, 3321, 3403, 3486, 3570, 3655, 3741, 3828,
   3916, 4005, 4095, 4186, 4278, 4371, 4465, 4560, 4656, 4753, 4851,
   4950, 5050], dtype=int32)

现在我得到了整个列表的CumSum

我在想，

0 > 1000 ==> 号继续

0+1 > 1000 ==> 号继续

...

990 + 45 > 1000 ==> 是的。打印 'MAX VALUE REACHED', 并停止计算

我期待这样的事情

array([   0,    1,    3,    6,   10,   15,   21,   28,   36,   45,   55,
         66,   78,   91,  105,  120,  136,  153,  171,  190,  210,  231,
        253,  276,  300,  325,  351,  378,  406,  435,  465,  496,  528,
        561,  595,  630,  666,  703,  741,  780,  820,  861,  903,  946,
        990])
MAX VALUE REACHED

有人可以帮助我将我的想法转化为代码吗？

谢谢！

Answer 1

鉴于克莱门特先生的评论，我希望到现在为止你已经有了这样的东西。

>>> total = 0
>>> i = 0
>>> while total < 1000:
...     total += i
...     i += 1
... 
>>> print (total)
1035

但是迟早有人应该建议您仔细查看 itertools 库以及 numpy。你的代码可以写得更紧凑，像这样。

>>> from itertools import count, accumulate, dropwhile
>>> next(dropwhile(lambda x: x<1000, accumulate(count())))
1035

这称为 functional programming。 count 是一个所谓的生成器，它可以生成可能无限的数字序列，在本例中为 0, 1, 2, 3, ...。 accumulate 产生可能无限的这些总和序列。 dropwhile 安排忽略该系列中不满足 lambda 条件的数字。最后 next 生成结果序列中的下一项。

Answer 2

我现在得到了这样的东西：

def cumsum(x):
q = np.array(range (0,x))
z = q.cumsum()
v = np.clip(z, 0, 1000)
solution = ['MAX VALUE REACHED' if i == 1000 else i for i in v]
if x == 0:
    return[0]
else:
    return solution

我的输出是这样的

[0,
 1,
 3,
 6,
 10,
 15,
 21,
 28,
 36,
 45,
 55,
 66,
 78,
 91,
 105,
 120,
 136,
 153,
 171,
 190,
 210,
 231,
 253,
 276,
 300,
 325,
 351,
 378,
 406,
 435,
 465,
 496,
 528,
 561,
 595,
 630,
 666,
 703,
 741,
 780,
 820,
 861,
 903,
 946,
 990,
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED',
 'MAX VALUE REACHED']

现在计算一次就得停止'MAX VALUE REACHED' 有什么建议吗？

建议的备选方案

而不是使用 clip 创建一个新列表，其中仅包含 cumsum 个少于 1,000 的项目，当您遇到一个至少为 1,000 的项目时，就会跳出循环。

import numpy as np

q = np.array(range(101)) 
z = q.cumsum()
temp = []
for _ in z:
    if _ < 1000:
        temp.append(_)
    else:
        break
solution = np.array(temp)
print (solution)
print('MAX VALUE REACHED')

输出：

[  0   1   3   6  10  15  21  28  36  45  55  66  78  91 105 120 136 153
 171 190 210 231 253 276 300 325 351 378 406 435 465 496 528 561 595 630
 666 703 741 780 820 861 903 946 990]
MAX VALUE REACHED

CumSum 直到达到某个值然后停止并打印 'MAX'

CumSum until certain value reached and then stop and print 'MAX'

python-3.x

cumsum