Question

我有一些带有一些数据的csv文件。我试图从csv文件中读取numpy数组，所以这里是程序的代码：

import numpy as np
train = csv.reader(open(sys.argv[1], 'r'))
X = []
y = []
for row in train:
    X.append(row[1:])
    y.append(row[0])
X = np.array(X)
y = np.array(y)

我知道Python语法很不寻常。那么有没有办法在类似的东西中编写转循环？

import numpy as np
train = csv.reader(open(sys.argv[1], 'r'))
X, y = [... for row in train]

Answer 1

为什么不使用np.loadtxt读取整个csv文件？

>>> from io import StringIO
>>> txt = '''
... 1, 2, 3
... 4, 5, 6
... 7, 8, 9'''
>>> 
>>> xs = np.loadtxt(StringIO(txt), delimiter=',')
>>> xs
array([[ 1.,  2.,  3.],
       [ 4.,  5.,  6.],
       [ 7.,  8.,  9.]])
>>> 
>>> x, y = xs[:, 1:], xs[:, 0]
>>> x
array([[ 2.,  3.],
       [ 5.,  6.],
       [ 8.,  9.]])
>>> y
array([ 1.,  4.,  7.])

在一行中从csv读取几个numpy数组

1 个答案: