如何使用python脚本从文本文件中提取数据？

我有python脚本，应该搜索数据文件，并将相关数据复制到单独的文件。这里是脚本：如何使用python脚本从文本文件中提取数据？

#!/usr/bin/env python 

import os 

os.system("grep \"x \" dynamics.out | awk '{print $2}' > coord.dat") 
os.system("grep \"Total\" dynamics.out | awk '{print $4}' > total.dat") 
os.system("grep \"Kinetic\" dynamics.out | awk '{print $4}' > kinetic.dat")

问题是，这部分，使coord.dat文件是完全错误的。 dynamics.out文件中的输出未按照此脚本中假定的方式排列。数据文件实际上是一个长期的一系列数据块的，看起来像这样：

time: 0.2fs 
coordinates 
C   3.952444338331  0.353499658087  0.155475597879 
C   2.898759709487  0.271561183058  2.878962426315 
C   0.377507660095  1.575527713456  2.766723501812 
N  -0.435656339866  0.616843403256  0.264424997127 
C   1.700335308734  1.369156629701  -1.411382740946 
C  -2.337147095089  -0.967913098150  -0.045537023463 
C  -3.526272967903  -1.434075863003  -2.507321890479 
C   1.622297308900  0.380583237194  -4.021983342405 
O  -3.540891745414  -1.784144627448  2.005202557948 
H   4.590691590007  -1.467822752968  -0.627674161136 
H   5.486618188590  1.704246328926  0.014750183919 
H   2.660849255805  -1.743362985878  3.501798747714 
H   4.277029595067  1.121286334364  4.194254865266 
H   0.568970284045  3.642407977900  2.660909012456 
H  -1.014510536177  1.242297828699  4.266572018582 
H  -3.406669591714  0.378282552422  -3.550366695442 
H  -5.529437662690  -2.075200692969  -2.212384192799 
H  -2.490387114770  -2.906665564518  -3.579439523150 
H   1.675087738572  3.514639806992  -1.458115996333 
H  -0.116965875674  1.068581149519  -5.163647181683 
H   1.470748269634  -1.655673714451  -4.142927345712 
H   3.361564138064  1.115048483423  -4.937771405417 
H  -5.134728946067  -2.640023263298  1.567623789643 
velocities 
     0.000241908669  0.000039611121  -0.000250932377 
     -0.000163805243  -0.000115366290  -0.000017375326 
     -0.000047784448  0.000248119899  -0.000074616012 
     0.000272673498  -0.000017362735  0.000399681421 
     -0.000326634443  -0.000254296236  0.000120448584 
     -0.000094363714  0.000239927614  -0.000271069374 
     0.000122625277  0.000053803004  -0.000088144918 
     -0.000112099948  -0.000143815691  0.000140925518 
     -0.000020483349  -0.000161160777  0.000050721656 
     0.000277228119  0.000550968890  -0.000249788972 
     0.000308946542  0.000944826745  0.000083253008 
     -0.001453065687  0.000249483273  -0.000194390979 
     0.000370071103  0.000328142273  -0.000594811431 
     0.000983242907  -0.000247664001  -0.000337676641 
     0.000702749595  -0.000531050917  -0.000068247339 
     -0.000913913436  -0.000822599342  -0.000519543480 
     0.000657300149  -0.0.000033192915 
     0.000763780031  0.000151892085  -0.000106941733 
     -0.000111349513  0.000591872099  0.000360147787 
     0.000283007739  0.000537032161  0.000183614425 
     -0.001766985000  0.001017499281  -0.000870068723 
     0.001560592306  -0.000636221326  0.001124910644 
     -0.000596019125  0.001094375746  0.000048984716 

Kinetic energy :  0.030613110934 
Electronic energy :  -60.105483063648 
Total energy  :  -60.074869952714 
Conservation  :  -0.000000051487 
self.forces: 
     -0.000751933584  -0.004126331042  -0.004033882094 
     -0.034302855990  0.029127675777  -0.007001211293 
     0.037731564948  -0.009915059812  0.020878531238 
     -0.109763802365  -0.102520873021  -0.034608644850 
     0.033373305433  0.018949006487  -0.015434320612 
     0.078807110369  0.101440274624  0.031960385836 
     0.027868883444  -0.012844760956  0.009625682828 
     0.011817203866  -0.011548503873  0.038027933611 
     -0.016951256413  -0.005848802217  -0.020755575427 
     0.002823354740  0.003214778324  -0.005974478408 
     -0.012101005124  -0.007850077809  0.000381372379 
     0.001958908572  -0.006446492464  0.003077496955 
     0.005728700900  -0.005220923285  -0.001710604936 
     -0.006358072353  -0.016410380723  -0.003938145281 
     0.000121143012  0.012930928986  -0.005592639661 
     0.008318475112  0.004530628154  0.009023640965 
     -0.010548513939  -0.005006070272  0.008756275583 
     -0.000601535778  -0.003075790288  -0.006209965764 
     -0.002729816846  -0.003390850759  -0.001421821138 
     -0.023967939963  0.000603482820  -0.016983439682 
     -0.006731466272  0.010586445711  -0.001984503303 
     0.009694983786  0.008555900046  0.002598629870 
     0.006564564487  0.004265795793  0.001319282998 
state for next step: 1

所以我需要的是从数据的每块（有成千上万的文件中）来获得一部分位于表示“坐标”的线和表示“速度”的线之间。我需要将它复制到一个文件中，这个文件中的编号为23（原子数）然后是空行，然后是这个数据，然后是23，空行，数据，...

如何重写脚本去做这个？或者有人可以推荐一些我可以学习的文献。我不知道Python的第一件事，但我在C和C++和Matlab中有一些经验，并且我理解编程的基本逻辑。很抱歉，这篇文章很长，但我认为提供一个数据样本会很有用。预先感谢您的帮助。

来源

2013-07-22 Marin

你在问什么，没有冒犯性，相当直接，在这里经常被问到：搜索stackoverflow并阅读文档总是一个好主意：http://stackoverflow.com/search？ q = python + read + text + file和http://stackoverflow.com/search?q=python+extract+data+file和http://docs.python.org/2/tutorial/inputoutput.html#reading-和写文件。你会想要使用一个列表，所以这应该也是有帮助的：http://docs.python.org/2/tutorial/datastructures.html 如果你需要更多帮助/澄清，随时编辑你的问题。 – seth

没有冒犯:)我知道这是非常基本的，它应该很容易做到，但正如我所说，我对Python一无所知，当我看着其他类似的问题时，我无法真正与我联系问题（代码），虽然我知道它们本质上非常相似。感谢您提供有关Python的链接，我会看看他们，并尝试自己做一些事情。 :) – Marin

没关系，我正努力通过学习C++现在，所以我只会回答你的问题，而不是一个自命不凡的家伙，哈哈。 – seth

你可以尝试这样的事：

whole_data = [] 
grab_lines = False 
with open('input','r') as atom_file: 
    molecule_data = ['23\n\n'] 
    for line in atom_file: 
     if line.startswith('coordinates'): 
      grab_lines = True 
      continue 
     elif line.startswith('velocities'): 
      grab_lines = False 
      if molecule_data: 
       #just checks that we aren't appending an empty list. 
       molecule_data.append('\n') 
       whole_data.append(molecule_data) 
       molecule_data = ['23\n\n'] 
     if grab_lines: #in python 'is True' is implicit for many types. 
      molecule_data.append(line) 

with open('output','w') as out_file: 
    for molecule in whole_data: 
     out_file.write(''.join(molecule))

我复制/粘贴输入数据了几次，所以我atom_file样子的内容：

time: 0.2fs 
coordinates 
C   3.952444338331  0.353499658087  0.155475597879 
C   2.898759709487  0.271561183058  2.878962426315 
C   0.377507660095  1.575527713456  2.766723501812 
N  -0.435656339866  0.616843403256  0.264424997127 
C   1.700335308734  1.369156629701  -1.411382740946 
C  -2.337147095089  -0.967913098150  -0.045537023463 
C  -3.526272967903  -1.434075863003  -2.507321890479 
C   1.622297308900  0.380583237194  -4.021983342405 
O  -3.540891745414  -1.784144627448  2.005202557948 
H   4.590691590007  -1.467822752968  -0.627674161136 
H   5.486618188590  1.704246328926  0.014750183919 
H   2.660849255805  -1.743362985878  3.501798747714 
H   4.277029595067  1.121286334364  4.194254865266 
H   0.568970284045  3.642407977900  2.660909012456 
H  -1.014510536177  1.242297828699  4.266572018582 
H  -3.406669591714  0.378282552422  -3.550366695442 
H  -5.529437662690  -2.075200692969  -2.212384192799 
H  -2.490387114770  -2.906665564518  -3.579439523150 
H   1.675087738572  3.514639806992  -1.458115996333 
H  -0.116965875674  1.068581149519  -5.163647181683 
H   1.470748269634  -1.655673714451  -4.142927345712 
H   3.361564138064  1.115048483423  -4.937771405417 
H  -5.134728946067  -2.640023263298  1.567623789643 
velocities 
     0.000241908669  0.000039611121  -0.000250932377 
     -0.000163805243  -0.000115366290  -0.000017375326 
     -0.000047784448  0.000248119899  -0.000074616012 
     0.000272673498  -0.000017362735  0.000399681421 
     -0.000326634443  -0.000254296236  0.000120448584 
     -0.000094363714  0.000239927614  -0.000271069374 
     0.000122625277  0.000053803004  -0.000088144918 
     -0.000112099948  -0.000143815691  0.000140925518 
     -0.000020483349  -0.000161160777  0.000050721656 
     0.000277228119  0.000550968890  -0.000249788972 
     0.000308946542  0.000944826745  0.000083253008 
     -0.001453065687  0.000249483273  -0.000194390979 
     0.000370071103  0.000328142273  -0.000594811431 
     0.000983242907  -0.000247664001  -0.000337676641 
     0.000702749595  -0.000531050917  -0.000068247339 
     -0.000913913436  -0.000822599342  -0.000519543480 
     0.000657300149  -0.0.000033192915 
     0.000763780031  0.000151892085  -0.000106941733 
     -0.000111349513  0.000591872099  0.000360147787 
     0.000283007739  0.000537032161  0.000183614425 
     -0.001766985000  0.001017499281  -0.000870068723 
     0.001560592306  -0.000636221326  0.001124910644 
     -0.000596019125  0.001094375746  0.000048984716 

Kinetic energy :  0.030613110934 
Electronic energy :  -60.105483063648 
Total energy  :  -60.074869952714 
Conservation  :  -0.000000051487 
self.forces: 
     -0.000751933584  -0.004126331042  -0.004033882094 
     -0.034302855990  0.029127675777  -0.007001211293 
     0.037731564948  -0.009915059812  0.020878531238 
     -0.109763802365  -0.102520873021  -0.034608644850 
     0.033373305433  0.018949006487  -0.015434320612 
     0.078807110369  0.101440274624  0.031960385836 
     0.027868883444  -0.012844760956  0.009625682828 
     0.011817203866  -0.011548503873  0.038027933611 
     -0.016951256413  -0.005848802217  -0.020755575427 
     0.002823354740  0.003214778324  -0.005974478408 
     -0.012101005124  -0.007850077809  0.000381372379 
     0.001958908572  -0.006446492464  0.003077496955 
     0.005728700900  -0.005220923285  -0.001710604936 
     -0.006358072353  -0.016410380723  -0.003938145281 
     0.000121143012  0.012930928986  -0.005592639661 
     0.008318475112  0.004530628154  0.009023640965 
     -0.010548513939  -0.005006070272  0.008756275583 
     -0.000601535778  -0.003075790288  -0.006209965764 
     -0.002729816846  -0.003390850759  -0.001421821138 
     -0.023967939963  0.000603482820  -0.016983439682 
     -0.006731466272  0.010586445711  -0.001984503303 
     0.009694983786  0.008555900046  0.002598629870 
     0.006564564487  0.004265795793  0.001319282998 
state for next step: 1 

    time: 0.2fs 
coordinates 
C   3.952444338331  0.353499658087  0.155475597879 
C   2.898759709487  0.271561183058  2.878962426315 
C   0.377507660095  1.575527713456  2.766723501812 
N  -0.435656339866  0.616843403256  0.264424997127 
C   1.700335308734  1.369156629701  -1.411382740946 
C  -2.337147095089  -0.967913098150  -0.045537023463 
C  -3.526272967903  -1.434075863003  -2.507321890479 
C   1.622297308900  0.380583237194  -4.021983342405 
O  -3.540891745414  -1.784144627448  2.005202557948 
H   4.590691590007  -1.467822752968  -0.627674161136 
H   5.486618188590  1.704246328926  0.014750183919 
H   2.660849255805  -1.743362985878  3.501798747714 
H   4.277029595067  1.121286334364  4.194254865266 
H   0.568970284045  3.642407977900  2.660909012456 
H  -1.014510536177  1.242297828699  4.266572018582 
H  -3.406669591714  0.378282552422  -3.550366695442 
H  -5.529437662690  -2.075200692969  -2.212384192799 
H  -2.490387114770  -2.906665564518  -3.579439523150 
H   1.675087738572  3.514639806992  -1.458115996333 
H  -0.116965875674  1.068581149519  -5.163647181683 
H   1.470748269634  -1.655673714451  -4.142927345712 
H   3.361564138064  1.115048483423  -4.937771405417 
H  -5.134728946067  -2.640023263298  1.567623789643 
velocities 
     0.000241908669  0.000039611121  -0.000250932377 
     -0.000163805243  -0.000115366290  -0.000017375326 
     -0.000047784448  0.000248119899  -0.000074616012 
     0.000272673498  -0.000017362735  0.000399681421 
     -0.000326634443  -0.000254296236  0.000120448584 
     -0.000094363714  0.000239927614  -0.000271069374 
     0.000122625277  0.000053803004  -0.000088144918 
     -0.000112099948  -0.000143815691  0.000140925518 
     -0.000020483349  -0.000161160777  0.000050721656 
     0.000277228119  0.000550968890  -0.000249788972 
     0.000308946542  0.000944826745  0.000083253008 
     -0.001453065687  0.000249483273  -0.000194390979 
     0.000370071103  0.000328142273  -0.000594811431 
     0.000983242907  -0.000247664001  -0.000337676641 
     0.000702749595  -0.000531050917  -0.000068247339 
     -0.000913913436  -0.000822599342  -0.000519543480 
     0.000657300149  -0.0.000033192915 
     0.000763780031  0.000151892085  -0.000106941733 
     -0.000111349513  0.000591872099  0.000360147787 
     0.000283007739  0.000537032161  0.000183614425 
     -0.001766985000  0.001017499281  -0.000870068723 
     0.001560592306  -0.000636221326  0.001124910644 
     -0.000596019125  0.001094375746  0.000048984716 

Kinetic energy :  0.030613110934 
Electronic energy :  -60.105483063648 
Total energy  :  -60.074869952714 
Conservation  :  -0.000000051487 
self.forces: 
     -0.000751933584  -0.004126331042  -0.004033882094 
     -0.034302855990  0.029127675777  -0.007001211293 
     0.037731564948  -0.009915059812  0.020878531238 
     -0.109763802365  -0.102520873021  -0.034608644850 
     0.033373305433  0.018949006487  -0.015434320612 
     0.078807110369  0.101440274624  0.031960385836 
     0.027868883444  -0.012844760956  0.009625682828 
     0.011817203866  -0.011548503873  0.038027933611 
     -0.016951256413  -0.005848802217  -0.020755575427 
     0.002823354740  0.003214778324  -0.005974478408 
     -0.012101005124  -0.007850077809  0.000381372379 
     0.001958908572  -0.006446492464  0.003077496955 
     0.005728700900  -0.005220923285  -0.001710604936 
     -0.006358072353  -0.016410380723  -0.003938145281 
     0.000121143012  0.012930928986  -0.005592639661 
     0.008318475112  0.004530628154  0.009023640965 
     -0.010548513939  -0.005006070272  0.008756275583 
     -0.000601535778  -0.003075790288  -0.006209965764 
     -0.002729816846  -0.003390850759  -0.001421821138 
     -0.023967939963  0.000603482820  -0.016983439682 
     -0.006731466272  0.010586445711  -0.001984503303 
     0.009694983786  0.008555900046  0.002598629870 
     0.006564564487  0.004265795793  0.001319282998 
state for next step: 1 

    time: 0.2fs 
coordinates 
C   3.952444338331  0.353499658087  0.155475597879 
C   2.898759709487  0.271561183058  2.878962426315 
C   0.377507660095  1.575527713456  2.766723501812 
N  -0.435656339866  0.616843403256  0.264424997127 
C   1.700335308734  1.369156629701  -1.411382740946 
C  -2.337147095089  -0.967913098150  -0.045537023463 
C  -3.526272967903  -1.434075863003  -2.507321890479 
C   1.622297308900  0.380583237194  -4.021983342405 
O  -3.540891745414  -1.784144627448  2.005202557948 
H   4.590691590007  -1.467822752968  -0.627674161136 
H   5.486618188590  1.704246328926  0.014750183919 
H   2.660849255805  -1.743362985878  3.501798747714 
H   4.277029595067  1.121286334364  4.194254865266 
H   0.568970284045  3.642407977900  2.660909012456 
H  -1.014510536177  1.242297828699  4.266572018582 
H  -3.406669591714  0.378282552422  -3.550366695442 
H  -5.529437662690  -2.075200692969  -2.212384192799 
H  -2.490387114770  -2.906665564518  -3.579439523150 
H   1.675087738572  3.514639806992  -1.458115996333 
H  -0.116965875674  1.068581149519  -5.163647181683 
H   1.470748269634  -1.655673714451  -4.142927345712 
H   3.361564138064  1.115048483423  -4.937771405417 
H  -5.134728946067  -2.640023263298  1.567623789643 
velocities 
     0.000241908669  0.000039611121  -0.000250932377 
     -0.000163805243  -0.000115366290  -0.000017375326 
     -0.000047784448  0.000248119899  -0.000074616012 
     0.000272673498  -0.000017362735  0.000399681421 
     -0.000326634443  -0.000254296236  0.000120448584 
     -0.000094363714  0.000239927614  -0.000271069374 
     0.000122625277  0.000053803004  -0.000088144918 
     -0.000112099948  -0.000143815691  0.000140925518 
     -0.000020483349  -0.000161160777  0.000050721656 
     0.000277228119  0.000550968890  -0.000249788972 
     0.000308946542  0.000944826745  0.000083253008 
     -0.001453065687  0.000249483273  -0.000194390979 
     0.000370071103  0.000328142273  -0.000594811431 
     0.000983242907  -0.000247664001  -0.000337676641 
     0.000702749595  -0.000531050917  -0.000068247339 
     -0.000913913436  -0.000822599342  -0.000519543480 
     0.000657300149  -0.0.000033192915 
     0.000763780031  0.000151892085  -0.000106941733 
     -0.000111349513  0.000591872099  0.000360147787 
     0.000283007739  0.000537032161  0.000183614425 
     -0.001766985000  0.001017499281  -0.000870068723 
     0.001560592306  -0.000636221326  0.001124910644 
     -0.000596019125  0.001094375746  0.000048984716 

Kinetic energy :  0.030613110934 
Electronic energy :  -60.105483063648 
Total energy  :  -60.074869952714 
Conservation  :  -0.000000051487 
self.forces: 
     -0.000751933584  -0.004126331042  -0.004033882094 
     -0.034302855990  0.029127675777  -0.007001211293 
     0.037731564948  -0.009915059812  0.020878531238 
     -0.109763802365  -0.102520873021  -0.034608644850 
     0.033373305433  0.018949006487  -0.015434320612 
     0.078807110369  0.101440274624  0.031960385836 
     0.027868883444  -0.012844760956  0.009625682828 
     0.011817203866  -0.011548503873  0.038027933611 
     -0.016951256413  -0.005848802217  -0.020755575427 
     0.002823354740  0.003214778324  -0.005974478408 
     -0.012101005124  -0.007850077809  0.000381372379 
     0.001958908572  -0.006446492464  0.003077496955 
     0.005728700900  -0.005220923285  -0.001710604936 
     -0.006358072353  -0.016410380723  -0.003938145281 
     0.000121143012  0.012930928986  -0.005592639661 
     0.008318475112  0.004530628154  0.009023640965 
     -0.010548513939  -0.005006070272  0.008756275583 
     -0.000601535778  -0.003075790288  -0.006209965764 
     -0.002729816846  -0.003390850759  -0.001421821138 
     -0.023967939963  0.000603482820  -0.016983439682 
     -0.006731466272  0.010586445711  -0.001984503303 
     0.009694983786  0.008555900046  0.002598629870 
     0.006564564487  0.004265795793  0.001319282998 
state for next step: 1

和内容我out_file样子：

23 

C   3.952444338331  0.353499658087  0.155475597879 
C   2.898759709487  0.271561183058  2.878962426315 
C   0.377507660095  1.575527713456  2.766723501812 
N  -0.435656339866  0.616843403256  0.264424997127 
C   1.700335308734  1.369156629701  -1.411382740946 
C  -2.337147095089  -0.967913098150  -0.045537023463 
C  -3.526272967903  -1.434075863003  -2.507321890479 
C   1.622297308900  0.380583237194  -4.021983342405 
O  -3.540891745414  -1.784144627448  2.005202557948 
H   4.590691590007  -1.467822752968  -0.627674161136 
H   5.486618188590  1.704246328926  0.014750183919 
H   2.660849255805  -1.743362985878  3.501798747714 
H   4.277029595067  1.121286334364  4.194254865266 
H   0.568970284045  3.642407977900  2.660909012456 
H  -1.014510536177  1.242297828699  4.266572018582 
H  -3.406669591714  0.378282552422  -3.550366695442 
H  -5.529437662690  -2.075200692969  -2.212384192799 
H  -2.490387114770  -2.906665564518  -3.579439523150 
H   1.675087738572  3.514639806992  -1.458115996333 
H  -0.116965875674  1.068581149519  -5.163647181683 
H   1.470748269634  -1.655673714451  -4.142927345712 
H   3.361564138064  1.115048483423  -4.937771405417 
H  -5.134728946067  -2.640023263298  1.567623789643 

23 

C   3.952444338331  0.353499658087  0.155475597879 
C   2.898759709487  0.271561183058  2.878962426315 
C   0.377507660095  1.575527713456  2.766723501812 
N  -0.435656339866  0.616843403256  0.264424997127 
C   1.700335308734  1.369156629701  -1.411382740946 
C  -2.337147095089  -0.967913098150  -0.045537023463 
C  -3.526272967903  -1.434075863003  -2.507321890479 
C   1.622297308900  0.380583237194  -4.021983342405 
O  -3.540891745414  -1.784144627448  2.005202557948 
H   4.590691590007  -1.467822752968  -0.627674161136 
H   5.486618188590  1.704246328926  0.014750183919 
H   2.660849255805  -1.743362985878  3.501798747714 
H   4.277029595067  1.121286334364  4.194254865266 
H   0.568970284045  3.642407977900  2.660909012456 
H  -1.014510536177  1.242297828699  4.266572018582 
H  -3.406669591714  0.378282552422  -3.550366695442 
H  -5.529437662690  -2.075200692969  -2.212384192799 
H  -2.490387114770  -2.906665564518  -3.579439523150 
H   1.675087738572  3.514639806992  -1.458115996333 
H  -0.116965875674  1.068581149519  -5.163647181683 
H   1.470748269634  -1.655673714451  -4.142927345712 
H   3.361564138064  1.115048483423  -4.937771405417 
H  -5.134728946067  -2.640023263298  1.567623789643 

23 

C   3.952444338331  0.353499658087  0.155475597879 
C   2.898759709487  0.271561183058  2.878962426315 
C   0.377507660095  1.575527713456  2.766723501812 
N  -0.435656339866  0.616843403256  0.264424997127 
C   1.700335308734  1.369156629701  -1.411382740946 
C  -2.337147095089  -0.967913098150  -0.045537023463 
C  -3.526272967903  -1.434075863003  -2.507321890479 
C   1.622297308900  0.380583237194  -4.021983342405 
O  -3.540891745414  -1.784144627448  2.005202557948 
H   4.590691590007  -1.467822752968  -0.627674161136 
H   5.486618188590  1.704246328926  0.014750183919 
H   2.660849255805  -1.743362985878  3.501798747714 
H   4.277029595067  1.121286334364  4.194254865266 
H   0.568970284045  3.642407977900  2.660909012456 
H  -1.014510536177  1.242297828699  4.266572018582 
H  -3.406669591714  0.378282552422  -3.550366695442 
H  -5.529437662690  -2.075200692969  -2.212384192799 
H  -2.490387114770  -2.906665564518  -3.579439523150 
H   1.675087738572  3.514639806992  -1.458115996333 
H  -0.116965875674  1.068581149519  -5.163647181683 
H   1.470748269634  -1.655673714451  -4.142927345712 
H   3.361564138064  1.115048483423  -4.937771405417 
H  -5.134728946067  -2.640023263298  1.567623789643

编辑：你可以用更换if grab_lines声明：

if grab_lines: #in python 'is True' is implicit for many types. 
    line = [line.split()[0]]+[str(float(element)*.529) for element in line.split()[1:]]+['\n'] 
    molecule_data.append('\t'.join(line))

的line中间部分称为list comprehension。如果其中任何一个真的不清楚，就问。

来源

2013-07-23 06:57:38 seth

非常感谢你的回答。还有一件事，在将它们写入输出之前，我如何将所有这些数字（当然不是23）乘以0.529？ – Marin

我尝试过使用：_def mult（x）：return x * 0.529 line = map（mult，line（2,3,4））_因为它是远程唯一的想法，我已经知道如何做到这一点将每行的第2,3,4个元素与0.529相乘），但看起来语法错误。 – Marin

我想我明白了。您已将线段拆分为段，您保留第一个（索引0）完整，其他（索引1结束）相乘。最后再次加入该行并将其附加到正在输出的变量中。对？ – Marin

grab_lines = False 
with open('input','r') as atom_file: 
    molecule_data = ['23\n\n'] 
    for line in atom_file: 
     if line.startswith('coordinates'): 
      grab_lines = True 
      continue 
     elif line.startswith('velocities'): 
      grab_lines = False 
      #if molecule_data: 
       #just checks that we aren't appending an empty list. 
       #molecule_data.append('\n') 
       #whole_data.append(molecule_data) 
       #molecule_data = ['23\n\n'] 
     if grab_lines: #in python 'is True' is implicit for many types. 
      new_line = molecule_data.append(line) 

with open('output','w') as out_file: 
    for molecule in molecule_data: 
     out_file.write(molecule) 
     #out_file.write(''.join(molecule))

来源

2016-02-16 13:53:15 user2532296

如何使用python脚本从文本文件中提取数据？

回答

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