如何将字符串和ndarray顺序写入文件？

Question

我有3个numpy ndarray（比如A，B，C，尺寸为2），其元素是＆＃39; type是浮点数。我想按以下格式按顺序将它们写入文件：

“first:”
A

"second:"
B

"third:"
C

我尝试了以下代码并得到了＃34; IndexError：元组索引超出范围＆＃34;

with open("out.txt", "wb") as f:
    np.savetxt(f,"A:")
    np.savetxt(f, A, fmt="%s")
    np.savetxt(f,"B:")
    np.savetxt(f, B, fmt='%s')
    np.savetxt(f,"C:")
    np.savetxt(f, C, fmt='%s')

然后我试了

with open("out.txt", "wb") as f:
   f.write("A:\n")
   np.savetxt(f, A, fmt="%s")
   f.write("B:\n")
   np.savetxt(f, B, fmt='%s')
   f.write("C:\n")
   np.savetxt(f, C, fmt='%s')

并得到＆＃34; TypeError：需要类似字节的对象，而不是＆＃39; str＆＃39;＆＃34;

提前致谢！