Python文件解析异常：仅执行首个解析函数？求多工具解决方案

• 需求：从输入文件提取两类行的字段：
  1. 以MEMRANGE开头的行：提取BASEVALUE、INSTANCE、SLAVEBUSINTERFACE的值，按指定格式输出
  2. 以PORT开头的行：提取CLKFREQUENCY、SIGNAME的值输出
• 故障：编写的Python代码中，两个解析函数单独测试均正常，但写入输出文件时仅第一个执行的函数有输出（当前输出仅包含PORT行结果，缺失MEMRANGE行内容），怀疑是文件访问操作有误
• 接受其他实现方案：sed、awk或grep

输入文件示例 #

MEMRANGE BASEVALUE=0x10000000 INSTANCE=uart0 SLAVEBUSINTERFACE=apb
MEMRANGE BASEVALUE=0x20000000 INSTANCE=spi0 SLAVEBUSINTERFACE=ahb
PORT CLKFREQUENCY=100000000 SIGNAME=clk_cpu
PORT CLKFREQUENCY=50000000 SIGNAME=clk_periph

原Python代码 #

def parse_memrange(line):
    parts = line.split()
    base = [p.split('=')[1] for p in parts if p.startswith('BASEVALUE=')][0]
    instance = [p.split('=')[1] for p in parts if p.startswith('INSTANCE=')][0]
    slave = [p.split('=')[1] for p in parts if p.startswith('SLAVEBUSINTERFACE=')][0]
    return f"Memory: {instance} @ {base} (Bus: {slave})"

def parse_port(line):
    parts = line.split()
    clk = [p.split('=')[1] for p in parts if p.startswith('CLKFREQUENCY=')][0]
    sig = [p.split('=')[1] for p in parts if p.startswith('SIGNAME=')][0]
    return f"Port: {sig} - {clk} Hz"

with open('input.txt', 'r') as infile, open('output.txt', 'w') as outfile:
    # 先处理PORT行
    for line in infile:
        line = line.strip()
        if line.startswith('PORT'):
            outfile.write(parse_port(line) + '\n')
    # 再处理MEMRANGE行
    for line in infile:
        line = line.strip()
        if line.startswith('MEMRANGE'):
            outfile.write(parse_memrange(line) + '\n')

当前输出（output.txt） #

Port: clk_cpu - 100000000 Hz
Port: clk_periph - 50000000 Hz

期望输出 #

Memory: uart0 @ 0x10000000 (Bus: apb)
Memory: spi0 @ 0x20000000 (Bus: ahb)
Port: clk_cpu - 100000000 Hz
Port: clk_periph - 50000000 Hz

Python代码修正 #

问题根源：第一次遍历文件后，文件指针已移动到文件末尾，第二次遍历无法读取任何内容。提供两种修复方式：

方法1：一次性读取所有行到列表 #

def parse_memrange(line):
    parts = line.split()
    base = [p.split('=')[1] for p in parts if p.startswith('BASEVALUE=')][0]
    instance = [p.split('=')[1] for p in parts if p.startswith('INSTANCE=')][0]
    slave = [p.split('=')[1] for p in parts if p.startswith('SLAVEBUSINTERFACE=')][0]
    return f"Memory: {instance} @ {base} (Bus: {slave})"

def parse_port(line):
    parts = line.split()
    clk = [p.split('=')[1] for p in parts if p.startswith('CLKFREQUENCY=')][0]
    sig = [p.split('=')[1] for p in parts if p.startswith('SIGNAME=')][0]
    return f"Port: {sig} - {clk} Hz"

with open('input.txt', 'r') as infile, open('output.txt', 'w') as outfile:
    # 读取所有行到列表，避免指针偏移问题
    lines = infile.readlines()
    # 先处理MEMRANGE行
    for line in lines:
        line = line.strip()
        if line.startswith('MEMRANGE'):
            outfile.write(parse_memrange(line) + '\n')
    # 再处理PORT行
    for line in lines:
        line = line.strip()
        if line.startswith('PORT'):
            outfile.write(parse_port(line) + '\n')

方法2：单循环处理所有行（更高效） #

def parse_memrange(line):
    parts = line.split()
    base = [p.split('=')[1] for p in parts if p.startswith('BASEVALUE=')][0]
    instance = [p.split('=')[1] for p in parts if p.startswith('INSTANCE=')][0]
    slave = [p.split('=')[1] for p in parts if p.startswith('SLAVEBUSINTERFACE=')][0]
    return f"Memory: {instance} @ {base} (Bus: {slave})"

def parse_port(line):
    parts = line.split()
    clk = [p.split('=')[1] for p in parts if p.startswith('CLKFREQUENCY=')][0]
    sig = [p.split('=')[1] for p in parts if p.startswith('SIGNAME=')][0]
    return f"Port: {sig} - {clk} Hz"

with open('input.txt', 'r') as infile, open('output.txt', 'w') as outfile:
    for line in infile:
        line = line.strip()
        if not line:
            continue
        if line.startswith('MEMRANGE'):
            outfile.write(parse_memrange(line) + '\n')
        elif line.startswith('PORT'):
            outfile.write(parse_port(line) + '\n')

AWK实现方案 #

一行命令完成需求，输出顺序为MEMRANGE在前、PORT在后：

awk '
/^MEMRANGE/ {
    for (i=2; i<=NF; i++) {
        split($i, arr, "=")
        if (arr[1] == "BASEVALUE") base = arr[2]
        if (arr[1] == "INSTANCE") inst = arr[2]
        if (arr[1] == "SLAVEBUSINTERFACE") bus = arr[2]
    }
    print "Memory: " inst " @ " base " (Bus: " bus ")"
}
/^PORT/ {
    for (i=2; i<=NF; i++) {
        split($i, arr, "=")
        if (arr[1] == "CLKFREQUENCY") clk = arr[2]
        if (arr[1] == "SIGNAME") sig = arr[2]
    }
    port_lines = port_lines "Port: " sig " - " clk " Hz\n"
}
END { print port_lines }
' input.txt > output.txt

SED实现方案 #

分两步处理，先提取MEMRANGE行，再追加PORT行结果：

# 提取并格式化MEMRANGE行，写入输出文件
sed -n 's/^MEMRANGE BASEVALUE=\([^ ]*\) INSTANCE=\([^ ]*\) SLAVEBUSINTERFACE=\([^ ]*\)/Memory: \2 @ \1 (Bus: \3)/p' input.txt > output.txt
# 提取并格式化PORT行，追加到输出文件
sed -n 's/^PORT CLKFREQUENCY=\([^ ]*\) SIGNAME=\([^ ]*\)/Port: \2 - \1 Hz/p' input.txt >> output.txt

内容的提问来源于stack exchange，提问作者user2532296