CSV数据转换需求：按keyn与assert规则追加列并删除行

可行的Awk解决方案 #

BEGIN { FS = OFS = "," }
keyn_prev = ""
has_processed_first = 0
need_append_code = 0
prev_line = ""

{
    if (need_append_code) {
        print prev_line "," $3
        need_append_code = 0
        has_processed_first = 1
        next
    }

    if ($1 != keyn_prev) {
        keyn_prev = $1
        has_processed_first = 0
        if ($2 == "\"1\"") {
            prev_line = $0
            need_append_code = 1
            next
        } else {
            print $0 ",\"0\""
            has_processed_first = 1
        }
    } else {
        print $0 ",\"0\""
    }
}

END {
    if (need_append_code) {
        print prev_line ",\"0\""
    }
}

代码逻辑解释 #

• 分隔符配置：开头指定CSV的输入/输出分隔符为逗号，保证列处理的正确性。
• 状态跟踪变量：
  • keyn_prev：记录上一行的keyn值，用于判断是否进入新的keyn分组。
  • has_processed_first：标记当前keyn的第一行是否已处理完成。
  • need_append_code：标记是否需要读取下一行的code值来追加到当前行。
  • prev_line：暂存需要追加code的keyn第一行内容。
• 新keyn分组处理：
  • 若当前keyn第一行的assert为"1"，暂存该行并标记需要读取下一行的code，跳过当前输出。
  • 若assert为"0"，直接追加"0"后输出，并标记第一行已处理。
• 同keyn后续行处理：无论第一行的assert值是什么，后续行统一追加"0"输出。
• 文件末尾兜底：如果最后一行是需要追加code的keyn第一行但无后续行，直接追加"0"输出避免遗漏。

输入输出示例 #

输入CSV #

"key1","1","code1"
"key1","0","code2"
"key1","1","code3"
"key2","0","code4"
"key2","1","code5"
"key3","1","code6"
"key3","0","code7"

输出CSV #

"key1","1","code1","code2"
"key1","1","code3","0"
"key2","0","code4","0"
"key2","1","code5","0"
"key3","1","code6","code7"

内容的提问来源于stack exchange，提问作者dsv87