使用python读取表格数据

Question

我有一个包含数字数据的文件，在表格format.It中总共有6列。我想在5维数组中读取并存储5列的值，并将第6列的值存储到另一个数组中。我尝试使用numpy的loadtxt()，但它将所有列加载到一个列中。甚至我尝试使用带有unpack参数的loadtext()，但是它将每一列存储到不同的变量中。我在"stackoverflow“中搜索同样类型的问题，但没有找到任何东西。下面是我的数据示例

5000    0   0.3048  71.3    0.00266337  121.301
6300    0   0.3048  71.3    0.00266337  119.541
8000    0   0.3048  71.3    0.00266337  117.151
10000   0   0.3048  71.3    0.00266337  115.391
12500   0   0.3048  71.3    0.00266337  112.241
16000   0   0.3048  71.3    0.00266337  108.721

Answer 1

将pandas包与read_csv、iloc和values方法配合使用：

import pandas as pd
from io import StringIO

data ="""
5000    0   0.3048  71.3    0.00266337  121.301
6300    0   0.3048  71.3    0.00266337  119.541
8000    0   0.3048  71.3    0.00266337  117.151
10000   0   0.3048  71.3    0.00266337  115.391
12500   0   0.3048  71.3    0.00266337  112.241
16000   0   0.3048  71.3    0.00266337  108.721
"""

df = pd.read_csv(StringIO(data), sep='\s+', header=None)

a = df.iloc[:, :5].values
b = df.iloc[:, 5].values

In [192]: a
Out[192]: 
array([[  5.00000000e+03,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  6.30000000e+03,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  8.00000000e+03,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  1.00000000e+04,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  1.25000000e+04,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  1.60000000e+04,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03]])

In [193]: b
Out[193]: array([ 121.301,  119.541,  117.151,  115.391,  112.241,  108.721])

Answer 2

如果您想要使用不带pandas的NumPy的解决方案，请考虑读入整个数据，然后使用np.hsplit

In [75]: data = np.loadtxt('data.txt')

In [76]: d, e = np.hsplit(data, (-1,))     # split at the final column

In [77]: d
Out[77]: 
array([[  5.00000000e+03,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  6.30000000e+03,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  8.00000000e+03,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  1.00000000e+04,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  1.25000000e+04,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03],
       [  1.60000000e+04,   0.00000000e+00,   3.04800000e-01,
          7.13000000e+01,   2.66337000e-03]])

In [78]: e
Out[78]: 
array([[ 121.301],
       [ 119.541],
       [ 117.151],
       [ 115.391],
       [ 112.241],
       [ 108.721]])