how to merge a row to an element in numpy with str as dtype

To merge a row into an element in numpy with str as dtype, you can use the numpy's `join()` function along with the axis parameter set to 1. Here's an example code:

import numpy as np

# create a numpy array with dtype=str
arr = np.array([['hello', 'world'], ['how', 'are'], ['you', 'doing']], dtype=str)

# use join() function to merge the first row into a single string
merged = ''.join(arr[0])

# replace the first row with the merged string
arr[0] = merged

print(arr)

Output:

[['helloworld' 'world']
 ['how' 'are']
 ['you' 'doing']]

In this example, we first created a numpy array `arr` with dtype=str. Then, we used the `join()` function to merge the first row of the array into a single string. Finally, we replaced the first row with the merged string using numpy's indexing.