python - 列表上的选择性迭代

Question

我有一个巨大的列表，如下所示:

[ '0', '21', '51', '67', '96', '102', '128', '130', '0', '11', '36', '53', '81', '86', '113', 116', '0', '21', '48', '64', '91', '95','125', '139', '166', '175', '200', '205']

我必须对列表的元素进行简单的减法，这样:

//Consider 2 variables a & b//

a should store the difference between 0-21 (it should be 21-0 to avoid negative values)

然后

b should store the difference between 21-51 (it should be 51-21 to avoid negative values)

然后再说

a should store the difference between 51-67 (it should be 67-51 to avoid negative values)

然后

b = 67-96
a = 96-102
b = 102-128
a = 128-130

130 和后面的 0 之间不应有减法。新的迭代应该从 0-11,11-36 开始，依此类推，直到遇到下一个 0。

我完全不知道如何继续这一步。

Answer 1

您对问题的描述仍然不清楚，据我了解，这可能就是您正在寻找的:

li = [ 0, '21', '51', '67', '96', '102', '128', '130', '0', '11', '36', '53', '81', '86', '113', '116', '0', '21', '48', '64', '91', '95','125', '139', '166', '175', '200', 205]   

# Convert all items to integers for calculations
li = [int(x) for x in li]

for x, y in zip(li, li[1:]):
    if y != 0:
        a = abs(x - y)      
        print '|%3d - %3d| = %3d' % (x, y, a)
    else:
        print ''

输出:

|  0 -  21| =  21
| 21 -  51| =  30
| 51 -  67| =  16
| 67 -  96| =  29
| 96 - 102| =   6
|102 - 128| =  26
|128 - 130| =   2

|  0 -  11| =  11
| 11 -  36| =  25
| 36 -  53| =  17
| 53 -  81| =  28
| 81 -  86| =   5
| 86 - 113| =  27
|113 - 116| =   3

|  0 -  21| =  21
| 21 -  48| =  27
| 48 -  64| =  16
| 64 -  91| =  27
| 91 -  95| =   4
| 95 - 125| =  30
|125 - 139| =  14
|139 - 166| =  27
|166 - 175| =   9
|175 - 200| =  25
|200 - 205| =   5