You get the error because NumPy's array is homogeneous, meaning it is a multidimensional table of elements all of the same type. This is different from a multidimensional list-of-lists in "regular" Python, where you can have objects of different type in a list.
Regular Python:
>>> CoverageACol = [[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]]
>>> CoverageACol[0][0] = "hello"
>>> CoverageACol
[['hello', 1, 2, 3, 4],
[5, 6, 7, 8, 9]]
NumPy:
>>> from numpy import *
>>> CoverageACol = arange(10).reshape(2,5)
>>> CoverageACol
array([[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]])
>>> CoverageACol[0,0] = "Hello"
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
/home/biogeek/<ipython console> in <module>()
ValueError: setting an array element with a sequence.
So, it depends on what you want to achieve, why do you want to store a string in an array filled for the rest with numbers? If that really is what you want, you can set the datatype of the NumPy array to string:
>>> CoverageACol = array(range(10), dtype=str).reshape(2,5)
>>> CoverageACol
array([['0', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S1')
>>> CoverageACol[0,0] = "Hello"
>>> CoverageACol
array([['H', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S1')
Notice that only the first letter of Hello
gets assigned. If you want the whole word to get assigned, you need to set an array-protocol type string:
>>> CoverageACol = array(range(10), dtype='a5').reshape(2,5)
>>> CoverageACol:
array([['0', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S5')
>>> CoverageACol[0,0] = "Hello"
>>> CoverageACol
array([['Hello', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S5')