python - 在没有循环的模式之前解析所有子字符串？

Question

我有一个很长的字符串，它由许多用空格分隔的数字组成（有时甚至会在其中抛出一个新行）。我想遍历字符串并将所有数字附加到数字开头之前的新列表中0.000000000000000000e+00。所以这是我的字符串示例：

my_string = '1.249132165057832031e+13 1.638194600635518555e+13 2.127995187558799219e+13 2.744617593148214062e+13 -2.558800658636701519e+28 5.918883595148564680e+30 3.603563681248702509e+31 4.325917213186498068e+31 4.911908042151239481e+31 4.463331378152286632e+31 3.684371076399113503e+31 2.500614504012405068e+31 9.997365425073173512e+30 -7.046725649106466938e+30 -2.192076417151744811e+31 -2.531287564917444482e+31 -6.962936418905874724e+30 3.281685507310205847e+31 9.241630178064907840e+31 1.730544785932614751e+32 2.619210949875333106e+32 2.984440142196566918e+32 8.964375812060072923e+31 -8.515727465135046667e+32 -3.425309034394939997e+33 -8.145884847188906515e+33 -9.922370830834364410e+33 -2.119464668318252366e+28 -1.689726703118075140e+27 1.440101653069986610e+26 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 6.186324149659251562e+13 8.113154959294240625e+13 1.053889122977165625e+14 1.359271226298647969e+14 -2.097046363337115528e+28 4.850777756495711585e+30 2.953274256558218597e+31 3.545273642763729060e+31 4.025456872055449111e+31 3.657581460085835446e+31 3.018816679659856350e+31 2.048223110003727437e+31 8.176806147340775115e+30 -5.796250740354887641e+30 -1.798839398031696094e+31 -2.076444435341100150e+31 -5.711669151245612857e+30 2.691583747083509247e+31 7.579958708961477309e+31 1.419395486743453834e+32 2.148287875274468622e+32 2.447859658750551118e+32 7.352862842410293685e+31 -6.984595303325589259e+32 -2.809449882735912952e+33 -6.681296633318354125e+33 -8.138406580426555140e+33 -1.740744048703962454e+28 -1.411749034480591280e+27 8.079362883576220633e+25 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00 0.000000000000000000e+00'

从这个字符串中，我最终想要的是：

new_list = ['1.440101653069986610e+26', '8.079362883576220633e+25']

我在想我会使用正则表达式，但这似乎有点棘手，因为我有一堆0.000000000000000000e+00事件组合在一起，我只想要在第一个零出现之前的非零数字。我也不能假设总是有相同数量的零组合在一起。

我也想过分割空间并迭代，但我的完整字符串实际上太长了，无法有效地做到这一点。我怎样才能做到这一点？

标签： pythonregexpython-2.7

Answer 1

您可以使用否定的lookbehind断言：

In [55]: re.findall(r'(\S+)(?<!0\.000000000000000000e\+00)\s+0\.000000000000000000e\+00', my_string)
Out[55]: ['1.440101653069986610e+26', '8.079362883576220633e+25']

正如@revo 在评论中提到的那样，使用负前瞻断言，可以改进正则表达式以提高性能：

([-+]?\d\.(?!0+e\+0+)\S+)\s+(?:0\.0+e\+00\s*)+

现场演示