my_list = [[1, 23, "python"], [1, "is", 24], ["fun", 97, 5]]

print("该列表是：")
print(my_list)

in_delete, out_delete = ",", " "

my_result = out_delete.join([in_delete.join([str(element) for element in sub]) for sub in my_list])

print("输出字符串是：")
print(my_result)

The list is :
[[1, 23, 'python'], [1, 'is', 24], ['fun', 97, 5]]
The output string is :
1,23,python 1,is,24 fun,97,5