【发布时间】：2017-02-16 17:36:28
【问题描述】：
我想计算 12 个月内的差异。每个月我都有不同的天数。在我的数据中，我的月份从 1 到 316 编号。我该如何做一个 for 循环，所以首先我有 1-12 个月的差异，然后再增加一个月（2-13）等等？我的数据如下所示：
1990-01-02 1.721 1
1990-01-03 1.839 1
1990-01-04 1.713 1
1990-01-05 1.713 1
1990-01-08 1.811 1
1990-01-09 1.810 1
1990-01-10 1.701 1
1990-01-11 1.733 1
1990-01-12 1.697 1
1990-01-15 1.675 1
1990-01-16 1.616 1
1990-01-17 1.635 1
1990-01-18 1.603 1
1990-01-19 1.601 1
1990-01-22 1.632 1
1990-01-23 1.671 1
1990-01-24 1.519 1
1990-01-25 1.563 1
1990-01-26 1.545 1
1990-01-29 1.565 1
1990-01-30 1.549 1
1990-01-31 1.555 1
1990-02-01 1.672 2
1990-02-02 1.778 2
1990-02-05 1.850 2
1990-02-06 1.986 2
1990-02-07 2.054 2
1990-02-08 2.173 2
1990-02-09 2.065 2
1990-02-12 2.091 2
1990-02-13 2.187 2
1990-02-14 2.213 2
1990-02-15 2.267 2
1990-02-19 2.283 2
1990-02-20 2.217 2
1990-02-21 2.192 2
1990-02-22 2.292 2
1990-02-23 2.257 2
1990-02-26 2.118 2
1990-02-28 2.117 2
1990-03-01 2.083 3
1990-03-02 2.180 3
1990-03-05 2.117 3
1990-03-06 2.082 3
1990-03-07 2.148 3
1990-03-08 2.159 3
1990-03-09 2.103 3
1990-03-12 2.083 3
1990-03-13 2.053 3
1990-03-14 2.029 3
1990-03-15 2.044 3
1990-03-16 2.032 3
1990-03-19 1.998 3
1990-03-20 2.038 3
1990-03-21 2.089 3
1990-03-22 2.029 3
1990-03-23 2.027 3
1990-03-27 2.013 3
1990-03-28 2.006 3
1990-03-29 2.038 3
1990-03-30 2.044 3
1990-04-02 1.921 4
1990-04-03 1.992 4
1990-04-04 1.982 4
1990-04-05 1.929 4
1990-04-06 1.853 4
1990-04-09 1.945 4
1990-04-10 1.839 4
1990-04-11 1.834 4
1990-04-12 1.869 4
1990-04-17 1.834 4
1990-04-18 1.801 4
1990-04-19 1.763 4
1990-04-20 1.719 4
1990-04-24 1.653 4
1990-04-25 1.739 4
1990-04-26 1.714 4
1990-04-27 1.791 4
1990-04-30 1.778 4
1990-05-02 1.857 5
1990-05-03 1.980 5
1990-05-04 2.062 5
1990-05-07 2.000 5
1990-05-08 1.927 5
1990-05-09 2.017 5
1990-05-10 1.955 5
1990-05-11 1.811 5
1990-05-14 1.757 5
1990-05-15 1.799 5
1990-05-16 1.774 5
1990-05-17 1.799 5
1990-05-18 1.820 5
1990-05-21 1.739 5
1990-05-22 1.858 5
1990-05-23 1.896 5
1990-05-25 1.876 5
1990-05-28 1.945 5
1990-05-29 2.010 5
1990-05-30 1.967 5
1990-05-31 1.963 5
1990-06-01 1.945 6
1990-06-05 1.953 6
1990-06-06 1.920 6
1990-06-07 1.944 6
1990-06-08 1.931 6
1990-06-11 1.916 6
1990-06-12 1.888 6
1990-06-13 1.917 6
1990-06-15 1.883 6
1990-06-18 1.838 6
1990-06-19 1.864 6
1990-06-20 1.969 6
1990-06-21 2.018 6
1990-06-22 1.961 6
1990-06-25 1.953 6
1990-06-26 1.915 6
1990-06-27 1.903 6
1990-06-28 1.897 6
1990-06-29 1.919 6
1990-07-02 1.953 7
1990-07-03 1.955 7
1990-07-04 2.070 7
1990-07-05 2.026 7
1990-07-06 2.026 7
1990-07-09 2.034 7
1990-07-10 1.995 7
1990-07-11 2.021 7
1990-07-12 2.005 7
1990-07-13 2.047 7
1990-07-16 2.039 7
1990-07-17 1.903 7
1990-07-18 1.949 7
1990-07-19 1.949 7
1990-07-20 2.009 7
1990-07-23 1.969 7
1990-07-24 1.959 7
1990-07-25 1.971 7
1990-07-26 1.995 7
1990-07-27 1.985 7
1990-07-30 1.887 7
1990-07-31 1.879 7
1990-08-01 1.822 8
1990-08-02 1.780 8
1990-08-03 1.683 8
1990-08-06 1.477 8
1990-08-07 1.541 8
1990-08-08 1.481 8
1990-08-09 1.513 8
1990-08-10 1.491 8
1990-08-13 1.457 8
1990-08-14 1.555 8
1990-08-15 1.655 8
1990-08-16 1.647 8
1990-08-17 1.585 8
1990-08-20 1.561 8
1990-08-21 1.423 8
1990-08-22 1.460 8
1990-08-23 1.435 8
1990-08-24 1.529 8
1990-08-27 1.571 8
1990-08-28 1.559 8
1990-08-29 1.545 8
1990-08-30 1.639 8
1990-08-31 1.629 8
1990-09-03 1.676 9
1990-09-04 1.620 9
1990-09-05 1.651 9
1990-09-06 1.591 9
1990-09-07 1.633 9
1990-09-10 1.672 9
1990-09-11 1.650 9
1990-09-12 1.726 9
1990-09-13 1.642 9
1990-09-14 1.621 9
1990-09-17 1.677 9
1990-09-18 1.665 9
1990-09-19 1.581 9
1990-09-20 1.508 9
1990-09-21 1.452 9
1990-09-24 1.354 9
1990-09-25 1.301 9
1990-09-26 1.345 9
1990-09-27 1.241 9
1990-09-28 1.215 9
1990-10-01 1.339 10
1990-10-02 1.318 10
1990-10-04 1.328 10
1990-10-08 1.277 10
1990-10-09 1.211 10
1990-10-10 1.264 10
1990-10-11 1.191 10
1990-10-12 1.249 10
1990-10-15 1.327 10
1990-10-16 1.295 10
1990-10-17 1.237 10
1990-10-18 1.392 10
1990-10-19 1.436 10
1990-10-22 1.420 10
1990-10-23 1.492 10
1990-10-24 1.460 10
1990-10-25 1.468 10
1990-10-26 1.418 10
1990-10-29 1.363 10
1990-10-30 1.368 10
1990-10-31 1.380 10
1990-11-01 1.340 11
1990-11-02 1.304 11
1990-11-05 1.272 11
1990-11-06 1.354 11
1990-11-07 1.252 11
1990-11-08 1.326 11
1990-11-09 1.299 11
1990-11-12 1.325 11
1990-11-13 1.353 11
1990-11-14 1.345 11
1990-11-15 1.369 11
1990-11-16 1.384 11
1990-11-19 1.450 11
1990-11-20 1.422 11
1990-11-22 1.502 11
1990-11-23 1.426 11
1990-11-26 1.370 11
1990-11-27 1.324 11
1990-11-28 1.293 11
1990-11-29 1.346 11
1990-11-30 1.430 11
1990-12-03 1.484 12
1990-12-04 1.460 12
1990-12-05 1.454 12
1990-12-06 1.493 12
1990-12-07 1.471 12
1990-12-10 1.493 12
1990-12-11 1.485 12
1990-12-12 1.451 12
1990-12-13 1.400 12
1990-12-14 1.402 12
1990-12-17 1.366 12
1990-12-18 1.350 12
1990-12-19 1.334 12
1990-12-20 1.193 12
1990-12-21 1.225 12
1990-12-27 1.183 12
1990-12-28 1.143 12
1991-01-02 1.133 13
1991-01-03 1.096 13
1991-01-04 1.129 13
1991-01-07 1.046 13
1991-01-08 1.112 13
1991-01-09 1.094 13
1991-01-10 1.110 13
1991-01-11 1.115 13
1991-01-14 1.074 13
1991-01-15 1.078 13
1991-01-16 0.978 13
1991-01-17 1.147 13
1991-01-18 1.036 13
1991-01-21 1.086 13
1991-01-22 1.059 13
1991-01-23 0.996 13
1991-01-24 1.037 13
1991-01-25 1.036 13
1991-01-28 1.012 13
1991-01-29 1.030 13
1991-01-30 1.067 13
1991-01-31 1.110 13
1991-02-01 1.094 14
1991-02-04 1.139 14
1991-02-05 1.146 14
1991-02-06 1.102 14
1991-02-07 1.145 14
1991-02-08 1.199 14
1991-02-11 1.242 14
1991-02-12 1.243 14
1991-02-13 1.256 14
1991-02-14 1.246 14
1991-02-15 1.440 14
1991-02-18 1.482 14
1991-02-19 1.476 14
1991-02-20 1.426 14
1991-02-21 1.482 14
1991-02-22 1.515 14
1991-02-25 1.561 14
1991-02-26 1.525 14
1991-02-27 1.559 14
1991-02-28 1.482 14
1991-03-01 1.438 15
1991-03-04 1.486 15
1991-03-05 1.526 15
1991-03-06 1.623 15
1991-03-07 1.603 15
1991-03-08 1.650 15
1991-03-11 1.681 15
1991-03-12 1.718 15
1991-03-13 1.688 15
1991-03-14 1.754 15
1991-03-15 1.720 15
1991-03-18 1.690 15
1991-03-19 1.708 15
1991-03-20 1.690 15
1991-03-21 1.619 15
1991-03-22 1.597 15
1991-03-25 1.650 15
1991-03-26 1.612 15
1991-03-27 1.601 15
1991-03-28 1.663 15
1991-04-02 1.746 16
1991-04-03 1.780 16
【问题讨论】：