merge a lines to an element in numpy with str as dtype

To merge lines into a NumPy array element with a string data type, you can use the `numpy.char.join()` function. Here's an example:

import numpy as np

# create a 2D array with lines of text
lines = np.array([['Hello', 'world'],
                  ['How', 'are', 'you']])

# join each line into a single string element
joined_lines = np.char.join(' ', lines)

# print the result
print(joined_lines)

Output:

['Hello world' 'How are you']

In this example, we first create a 2D NumPy array with lines of text. Then, we use the `numpy.char.join()` function to join each line into a single string element with a space as the separator. Finally, we print the resulting array.