当我们在生成数据的时候，常用到%d方式进行格式化生成数据。
比如要生成11位的手机号，可以这样：
def test_create_data():
data = ['138%08d' %x for x in range(20)]
print(data)
当填充内容不足8位的时候，用0进行填充输出内容：
['13800000000', '13800000001', '13800000002', '13800000003', '13800000004', '13800000005', '13800000006', '13800000007', '13800000008', '13800000009', '13800000010', '13800000011', '13800000012', '13800000013', '13800000014', '13800000015', '13800000016', '13800000017', '13800000018', '13800000019']
详细用法参考博客：https://blog.csdn.net/lijing742180/article/details/80788422