str_a = "123" int_a = int(str_a) print("num2+1: %d"%(int_a + 1)) # num2+1: 124 str_b = "123.12" double_a = float(str_b) print("num2: %f"%(double_a + 1.0)) # num2: 124.120000 num = 123 str_num = str(num) print("hello %s"%str_num) # hello 123