Python - strings and integers in Numpy array

Question

I want to create an array with 3 columns. The first one a string, the other two integers used for calculations. Then more rows will be added through the append function (below).

Answer 1

To have such a mixed datatype data, we could use object as dtype before appending or stacking -

a = np.array([["String",1,2]], dtype=object)
b = [["another string", 3, 4]]
a = np.vstack((a,np.asarray(b,object)))

Sample run -

In [40]: a = np.array([["String",1,2]], dtype=object)

In [41]: b = [["another string", 3, 4]]

In [42]: np.vstack((a,np.asarray(b,object)))
Out[42]: 
array([['String', 1, 2],
       ['another string', 3, 4]], dtype=object)