如何使用正则表达式拆分字符串？答案

【问题标题】：How to split a string using regex?如何使用正则表达式拆分字符串？
【发布时间】：2022-01-15 05:24:44
【问题描述】：

我正在尝试用每个“_”字符拆分 ad_content，但我不知道为什么我不能超过第 9 个拆分词 (splits[SAFE_OFFSET(8)] AS objective)。

这是我正在使用的查询：

SELECT
    ad_content,
    splits[SAFE_OFFSET(0)] AS country,
    splits[SAFE_OFFSET(1)] AS product,
    splits[SAFE_OFFSET(2)] AS budget,
    splits[SAFE_OFFSET(3)] AS source,
    splits[SAFE_OFFSET(4)] AS campaign,
    splits[SAFE_OFFSET(5)] AS audience,
    splits[SAFE_OFFSET(6)] AS route_type,
    splits[SAFE_OFFSET(7)] AS business,
    splits[SAFE_OFFSET(8)] AS objective,
    splits[SAFE_OFFSET(9)] AS format,
    splits[SAFE_OFFSET(10)] AS nnn,
    splits[SAFE_OFFSET(11)] AS date,
FROM (
  SELECT
    AD_CONTENT,
    SPLIT(REGEXP_REPLACE(
            AD_CONTENT,
            r'([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_([^_]+)_(.+)',
            r'\1|\2|\3|\4|\5|\6|\7|\8|\9|\10|\11|\12'),
          '|') AS splits
  FROM ga_digital_marketing

例如，ad_content = us_latam_perf_facebook_black-friday_bbdd-push_SCL-CCP_domestic_conversion_push_all_20210906

这是使用上面查询的结果：

ad_content	country	product	budget	source	campaign	audience	route_type	business	objective	format	nnn	date
us_latam_perf_facebook_black-friday_bbdd-push_SCL-CCP_domestic_conversion_push_all_20210906	us	latam	perf	facebook	black-friday	bbdd-push	SCL-CCP	domestic	conversion	us0	us1	us2

正如您在上面看到的，格式列 (splits[SAFE_OFFSET(9)] AS format) 没有正确给出结果。

我相信问题出在：r'\1|\2|\3|\4|\5|\6|\7|\8|\9|\10|\11|\12') 因为可能 |\10 的数字 0 没有将其识别为数字而是字符串。这就是为什么我有 us0 us1 和 us2

有解决这个限制的办法吗？

还有其他方法可以拆分 ad_content 示例吗？

【问题讨论】：

对，\n 反向引用语法通常支持从 1 到 9 的组。试试$10、$11 和$12。
@WiktorStribiżew 感谢您的评论。但它没有奏效。控制台向我显示：“无效的 REGEXP_REPLACE 模式：重写架构错误：'\' 必须后跟一个数字或 '\'”

标签： sql regex google-bigquery regexp-replace

【解决方案1】：

BigQuery 的 REGEXP_REPLACE 仅支持 \1 到 \9 - 这就是原因！

有解决这个限制的办法吗？

改用下面的方法

SELECT
    -- ad_content,
    splits[SAFE_OFFSET(0)] AS country,
    splits[SAFE_OFFSET(1)] AS product,
    splits[SAFE_OFFSET(2)] AS budget,
    splits[SAFE_OFFSET(3)] AS source,
    splits[SAFE_OFFSET(4)] AS campaign,
    splits[SAFE_OFFSET(5)] AS audience,
    splits[SAFE_OFFSET(6)] AS route_type,
    splits[SAFE_OFFSET(7)] AS business,
    splits[SAFE_OFFSET(8)] AS objective,
    splits[SAFE_OFFSET(9)] AS format,
    splits[SAFE_OFFSET(10)] AS nnn,
    splits[SAFE_OFFSET(11)] AS date,
FROM (
  SELECT
    AD_CONTENT,
    SPLIT(AD_CONTENT, '_') AS splits
  FROM ga_digital_marketing
)

如果应用于您的问题中的样本 - 输出是

【讨论】：

很高兴它对你有用。也考虑投票赞成答案:o)