代码如下：
barcode_list = [4, 4, 4, 4, 6, 7, 8, 9, 90, 9]
list1 = []
for i in range(len(barcode_list)):
    if barcode_list[i] not in list1:
        list1.append(barcode_list[i])
print(list1)

out：[4, 6, 7, 8, 9, 90]