Excel to text file Mismatch between array dtype ('<U12') and format specifier ('%.18e')

Question

Currently I am:

1. extracting colums from an Excel sheet
2. Saving them as a matrix

I would like to save the new matrix in a text file

    import pandas as pd
    import os, sys
    import pandas as pd
    import numpy as np
    from openpyxl import load_workbook
    # Reading an excel file using Python 
    import xlrd 
    
    #or if your file is tab delimited '\t':
    df = pd.read_csv('batchTest2.txt', sep='\t')
    
    #To save to excel file add the following:
    df.to_excel('output.xlsx', 'Sheet1')
    
    # Give the location of the file 
    loc = ("outputUPDATED.xlsx") 
    wb = xlrd.open_workbook(loc) 
    sheet = wb.sheet_by_index(0)   
    
    #extract and save file
    for i in range(sheet.nrows): 
    matrix= [sheet.cell_value(i, 29),sheet.cell_value(i, 30),sheet.cell_value(i, 31),sheet.cell_value(i, 32),sheet.cell_value(i, 33),sheet.cell_value(i, 34),sheet.cell_value(i, 35),sheet.cell_value(i, 36),sheet.cell_value(i, 37),sheet.cell_value(i, 38),sheet.cell_value(i, 39),sheet.cell_value(i, 41),sheet.cell_value(i, 42),sheet.cell_value(i, 43),sheet.cell_value(i, 44),sheet.cell_value(i, 45),sheet.cell_value(i, 46),sheet.cell_value(i, 50)]
    data=np.array(matrix)
    with open("ModifiedBatch.txt", "w") as abc:
        np.savetxt(abc, data, delimiter=",")

But I get an error:

% (str(X.dtype), format))

TypeError: Mismatch between array dtype ('<U12') and format specifier ('%.18e')

I really tried to understand and look up different solutions, but I am still new at this. Right now I am thinking it has something to do with the format, but don't know what and how to fix it.