我是 Phyton 的新手。我有这个列表:
[
'0 214.0 1.55E-02 233.6',
'10 205.0 6.470E-03 228.5',
'20 188.3 2.630E-03 218.8',
'30 175.0 9.800E-04 211.0',
'40 162.4 3.400E-04 203.6',
'50 152.2 1.080E-04 197.0',
'60 144.2 3.180E-05 191.6',
'70 139.5 8.730E-06 188.4',
'80 139.0 2.290E-06 187.9',
'90 139.0 6.010E-07 188.2',
'100 139.0 1.590E-07 188.1',
'110 149.4 4.140E-08 195.5',
'120 159.7 1.190E-08 202.5',
'130 170.0 3.760E-09 208.6',
'140 245.1 1.090E-09 251.9',
'150 288.6 4.730E-10 275.5'
]
有 17 个元素。每个元素都有 4 个“子元素”，我想要一个包含 17X4 元素的列表。
即，每个数字 (0, 214.0, 1.55E-02, 233.6) 都应该是我列表中的一个元素。
我该怎么做？
请您参考如下方法:
好吧，数字由空格分隔。 str.split(..) 正在做的就是将字符串按照一定的分割字符串变成字符串。
所以你可以使用list comprehension [1]:
[list(<b>x.split()</b>) for x in mylist]给出:
>>> [list(x.split()) for x in mylist]
[['0', '214.0', '1.55E-02', '233.6'], ['10', '205.0', '6.470E-03', '228.5'], ['20', '188.3', '2.630E-03', '218.8'], ['30', '175.0', '9.800E-04', '211.0'], ['40', '162.4', '3.400E-04', '203.6'], ['50', '152.2', '1.080E-04', '197.0'], ['60', '144.2', '3.180E-05', '191.6'], ['70', '139.5', '8.730E-06', '188.4'], ['80', '139.0', '2.290E-06', '187.9'], ['90', '139.0', '6.010E-07', '188.2'], ['100', '139.0', '1.590E-07', '188.1'], ['110', '149.4', '4.140E-08', '195.5'], ['120', '159.7', '1.190E-08', '202.5'], ['130', '170.0', '3.760E-09', '208.6'], ['140', '245.1', '1.090E-09', '251.9'], ['150', '288.6', '4.730E-10', '275.5']]
注意这里的元素是strings，如果要float可以这样写:
[[<b>float(y)</b> for y in x.split()] for x in mylist]给出:
>>> [[float(y) for y in x.split()] for x in mylist]
[[0.0, 214.0, 0.0155, 233.6], [10.0, 205.0, 0.00647, 228.5], [20.0, 188.3, 0.00263, 218.8], [30.0, 175.0, 0.00098, 211.0], [40.0, 162.4, 0.00034, 203.6], [50.0, 152.2, 0.000108, 197.0], [60.0, 144.2, 3.18e-05, 191.6], [70.0, 139.5, 8.73e-06, 188.4], [80.0, 139.0, 2.29e-06, 187.9], [90.0, 139.0, 6.01e-07, 188.2], [100.0, 139.0, 1.59e-07, 188.1], [110.0, 149.4, 4.14e-08, 195.5], [120.0, 159.7, 1.19e-08, 202.5], [130.0, 170.0, 3.76e-09, 208.6], [140.0, 245.1, 1.09e-09, 251.9], [150.0, 288.6, 4.73e-10, 275.5]]
请注意，这些是 float 列表的列表。如果您想要一个平面列表，您可以使用:
[float(y) for x in mylist for y in x.split()]
生成:
>>> [float(y) for x in mylist for y in x.split()]
[0.0, 214.0, 0.0155, 233.6, 10.0, 205.0, 0.00647, 228.5, 20.0, 188.3, 0.00263, 218.8, 30.0, 175.0, 0.00098, 211.0, 40.0, 162.4, 0.00034, 203.6, 50.0, 152.2, 0.000108, 197.0, 60.0, 144.2, 3.18e-05, 191.6, 70.0, 139.5, 8.73e-06, 188.4, 80.0, 139.0, 2.29e-06, 187.9, 90.0, 139.0, 6.01e-07, 188.2, 100.0, 139.0, 1.59e-07, 188.1, 110.0, 149.4, 4.14e-08, 195.5, 120.0, 159.7, 1.19e-08, 202.5, 130.0, 170.0, 3.76e-09, 208.6, 140.0, 245.1, 1.09e-09, 251.9, 150.0, 288.6, 4.73e-10, 275.5]
如果您想批量进行矩阵 或向量 计算，通常会使用像numpy 这样的库。您可以按如下方式在 numpy 中导入数据:
<b>import numpy as np</b>
np.fromstring(' '.join(mylist),sep=' ')制作:
>>> np.fromstring(' '.join(mylist),sep=' ')
array([ 0.00000000e+00, 2.14000000e+02, 1.55000000e-02,
2.33600000e+02, 1.00000000e+01, 2.05000000e+02,
6.47000000e-03, 2.28500000e+02, 2.00000000e+01,
1.88300000e+02, 2.63000000e-03, 2.18800000e+02,
3.00000000e+01, 1.75000000e+02, 9.80000000e-04,
2.11000000e+02, 4.00000000e+01, 1.62400000e+02,
3.40000000e-04, 2.03600000e+02, 5.00000000e+01,
1.52200000e+02, 1.08000000e-04, 1.97000000e+02,
6.00000000e+01, 1.44200000e+02, 3.18000000e-05,
1.91600000e+02, 7.00000000e+01, 1.39500000e+02,
8.73000000e-06, 1.88400000e+02, 8.00000000e+01,
1.39000000e+02, 2.29000000e-06, 1.87900000e+02,
9.00000000e+01, 1.39000000e+02, 6.01000000e-07,
1.88200000e+02, 1.00000000e+02, 1.39000000e+02,
1.59000000e-07, 1.88100000e+02, 1.10000000e+02,
1.49400000e+02, 4.14000000e-08, 1.95500000e+02,
1.20000000e+02, 1.59700000e+02, 1.19000000e-08,
2.02500000e+02, 1.30000000e+02, 1.70000000e+02,
3.76000000e-09, 2.08600000e+02, 1.40000000e+02,
2.45100000e+02, 1.09000000e-09, 2.51900000e+02,
1.50000000e+02, 2.88600000e+02, 4.73000000e-10,
2.75500000e+02])
