python - Numpy savetxt 异构数据

Question

我有两个数组 A 和 B，这样:

A.shape 是 (N, 1) 并且 dtype 是 int。B.shape为(N, M)，dtype为float。

数组 A 包含 ids/序列号。信息。我想将 A 和 B 写在一个保留数据类型的单个文件中，这样每一行都包含 A[i] 和 B[i, :] 即

A[0], B[0, 0], B[0, 1], ..... , B[0, M-1]
A[1], B[1, 0], B[1, 1], ..... , B[1, M-1]
.
.
.
and so on.

我该怎么做？

Answer 1

在调用 savetxt() 时使用 fmt="%g":

import numpy as np
a = np.random.randint(0, 100, 10)
b = np.random.rand(10, 3)

v = np.hstack((a[:,None],b))

import io

t = io.BytesIO()

np.savetxt(t, v, fmt="%g", delimiter=",")
print t.getvalue()

这是输出:

58,0.565189,0.865103,0.508969
23,0.916723,0.921158,0.0831125
59,0.277719,0.0093567,0.842342
2,0.647174,0.841386,0.26473
98,0.397821,0.552821,0.16494
62,0.369808,0.146442,0.569618
35,0.703737,0.288476,0.433288
94,0.756107,0.396098,0.896038
67,0.638921,0.891554,0.680056
82,0.449198,0.978571,0.116202