读取分隔文本文件时如何展平AAA/ABV/ABP嵌套记录结构？

我有一个竖线分隔的文本文件，内容如下：

AAA|C0421002|D|20180102091621|CD|UKDC|PB|PORTAL|301873|OPER|
ABV|E_ABERDARE|20161113|RF|16|20171229|
ABP|1|F|.051|I|
ABP|2|F|.047|I|
ABP|3|F|.019|I|
ABV|E_ASHWW-1|20161113|RF|16|20171229|
ABP|1|F|0|E|
ABP|2|F|0|E|
ABP|3|F|0|E|
ABV|E_ASLVW-1|20161113|RF|16|20171229|
ABP|1|F|1.204|E|
ABP|2|F|.974|E|
ABP|3|F|1.025|E|
AAA|C0421002|D|20180108092341|CD|UKDC|PB|PORTAL|302513|OPER|
ABV|E_ABERDARE|20161117|RF|16|20180105|
ABP|1|F|.051|I|
ABP|2|F|.048|I|
ABP|3|F|.041|I|
ABV|E_ASHWW-1|20161117|RF|16|20180105|
ABP|1|F|0|E|
ABP|2|F|0|E|
ABP|3|F|0|E|
ABV|E_ASLVW-1|20161117|RF|16|20180105|
ABP|1|F|5.487|E|
ABP|2|F|5.485|E|
ABP|3|F|5.484|E|

需要将每个ABV记录与其上方最近的AAA记录、下方对应的所有ABP记录合并为一行，目标格式如下：

AAA|C0421002|D|20180102091621|CD|UKDC|PB|PORTAL|301873|OPER|ABV|E_ABERDARE|20161113|RF|16|20171229|ABP|1|F|.051|I|ABP|2|F|.047|I|ABP|3|F|.019|I|
AAA|C0421002|D|20180102091621|CD|UKDC|PB|PORTAL|301873|OPER|ABV|E_ASHWW-1|20161113|RF|16|20171229|ABP|1|F|0|E|ABP|2|F|0|E|ABP|3|F|0|E|
AAA|C0421002|D|20180102091621|CD|UKDC|PB|PORTAL|301873|OPER|ABV|E_ASLVW-1|20161113|RF|16|20171229|ABP|1|F|1.204|E|ABP|2|F|.974|E|ABP|3|F|1.025|E|
AAA|C0421002|D|20180108092341|CD|UKDC|PB|PORTAL|302513|OPER|ABV|E_ABERDARE|20161117|RF|16|20180105|ABP|1|F|.051|I|ABP|2|F|.048|I|ABP|3|F|.041|I|
AAA|C0421002|D|20180108092341|CD|UKDC|PB|PORTAL|302513|OPER|ABV|E_ASHWW-1|20161117|RF|16|20180105|ABP|1|F|0|E|ABP|2|F|0|E|ABP|3|F|0|E|
AAA|C0421002|D|20180108092341|CD|UKDC|PB|PORTAL|302513|OPER|ABV|E_ASLVW-1|20161117|RF|16|20180105|ABP|1|F|5.487|E|ABP|2|F|5.485|E|ABP|3|F|5.484|E|

尝试用for循环实现但未成功，求解决方法。

解决方案 #

方法1：Python实现 #

通过逐行读取文件，维护当前的AAA、ABV记录以及ABP记录列表，当遇到新的AAA或ABV时，将上一组关联记录合并输出。

current_aaa = ""
current_abv = ""
abp_lines = []

# 替换为你的输入文件路径和输出文件路径
with open("input.txt", "r") as f, open("output.txt", "w") as out_f:
    for line in f:
        line = line.strip()
        if not line:
            continue
        if line.startswith("AAA|"):
            # 输出上一组未处理的ABV+ABP
            if current_abv and abp_lines:
                merged = current_aaa + current_abv + "".join(abp_lines)
                out_f.write(merged + "\n")
            current_aaa = line
            current_abv = ""
            abp_lines = []
        elif line.startswith("ABV|"):
            # 输出上一组未处理的ABV+ABP
            if current_abv and abp_lines:
                merged = current_aaa + current_abv + "".join(abp_lines)
                out_f.write(merged + "\n")
            current_abv = line
            abp_lines = []
        elif line.startswith("ABP|"):
            abp_lines.append(line)
    # 处理最后一组记录
    if current_abv and abp_lines:
        merged = current_aaa + current_abv + "".join(abp_lines)
        out_f.write(merged + "\n")

方法2：awk实现 #

利用awk的状态变量保存当前的AAA、ABV和ABP内容，逐行判断并合并输出。

BEGIN {
    FS = ""  # 按字符读取，避免竖线分隔符干扰开头判断
}

/^AAA\|/ {
    if (abv != "" && abp != "") {
        print aaa abv abp
    }
    aaa = $0
    abv = ""
    abp = ""
    next
}

/^ABV\|/ {
    if (abv != "" && abp != "") {
        print aaa abv abp
    }
    abv = $0
    abp = ""
    next
}

/^ABP\|/ {
    abp = abp $0
    next
}

END {
    if (abv != "" && abp != "") {
        print aaa abv abp
    }
}

使用方式：将上述代码保存为merge.awk，执行以下命令处理文件：

awk -f merge.awk input.txt > output.txt

内容的提问来源于stack exchange，提问作者Jason Grotto