open_list = open("my_list.txt")
num_list1 = []

for line in open("my_list.txt"):
    line = line.strip()
    num_list1.append(line)
    print(num_list1)             # this is printing my list perfect
                                 # ['15,57,14,33,72,79,26,56,42,40'] is what
                                 #  prints, which is what im looking for


temp = num_list1[0]              # this is where im running into issues
num_list1[0] = num_list1[2]
num_list1[2] = temp
print(num_list1)