numpy.core.defchararray.join

In [1]: import numpy as np
   ...: a=np.array([1,2,3,4,5,6]).reshape(2,3).astype("str")
   ...: a
Out[1]: 
array([['1', '2', '3'],
       ['4', '5', '6']], 
      dtype=')
# 使用"."连接a[0]行
In [2]: ".".join(a[0])
Out[2]: '1.2.3'
# 使用"."连接a,纵向循环
In [3]: np.apply_along_axis("-".join, 1, a)
Out[3]: 
array(['1-2-3', '4-5-6'], 
      dtype=')