Python3如何让dbg调试打印自动输出变量名与对应数值？

核心思路 #

通过Python的inspect模块获取dbg函数调用处的源码，解析出传入参数的原始表达式字符串，再和实际参数值配对格式化输出，全程不需要修改现有代码里的dbg调用逻辑，完全兼容你原来的一键开关调试的使用习惯。

完整实现代码 #

import inspect
import re

def dbg(*args):
    # 获取调用dbg的栈帧信息
    caller_stack = inspect.stack()[1]
    # 读取调用位置所在的源码段
    source_lines, start_line = inspect.getsourcelines(caller_stack.frame)
    call_offset = caller_stack.lineno - start_line
    
    # 处理跨多行的dbg调用，匹配完整的dbg(...)范围
    raw_call_code = ""
    bracket_count = 0
    in_string_tag = None
    for line_idx in range(call_offset, len(source_lines)):
        current_line = source_lines[line_idx]
        for char_idx, char in enumerate(current_line):
            # 跳过字符串内部的括号，避免解析错误
            if char in ("'", '"') and (char_idx == 0 or current_line[char_idx-1] != "\\"):
                if in_string_tag == char:
                    in_string_tag = None
                elif in_string_tag is None:
                    in_string_tag = char
            if in_string_tag is None:
                if char == "(":
                    bracket_count += 1
                elif char == ")":
                    bracket_count -= 1
                    if bracket_count == 0:
                        raw_call_code += current_line[:char_idx+1]
                        break
        if bracket_count == 0:
            break
        raw_call_code += current_line
    
    # 提取dbg的参数表达式字符串
    param_match = re.search(r"dbg\((.*)\)", raw_call_code, re.DOTALL)
    if not param_match:
        return
    param_raw_str = param_match.group(1)
    
    # 拆分多个参数，处理嵌套括号、字符串内逗号的场景
    param_expr_list = []
    current_expr = ""
    nested_level = 0
    in_str = None
    for char in param_raw_str:
        if char in ("'", '"') and (not current_expr or current_expr[-1] != "\\"):
            if in_str == char:
                in_str = None
            elif in_str is None:
                in_str = char
        if in_str is None:
            if char == "(":
                nested_level += 1
            elif char == ")":
                nested_level -= 1
            elif char == "," and nested_level == 0:
                param_expr_list.append(current_expr.strip())
                current_expr = ""
                continue
        current_expr += char
    if current_expr.strip():
        param_expr_list.append(current_expr.strip())
    
    # 格式化输出
    output_items = [f"{expr} = {repr(val)}" for expr, val in zip(param_expr_list, args)]
    print(", ".join(output_items))

# 关闭调试时直接替换为下面的空函数即可
# def dbg(*args): pass

效果验证 #

用你示例的场景测试：

x = 0
y = 15
def f(v):
    return 32

dbg(x, y, f(x))

运行后输出结果完全符合要求：

x = 0, y = 15, f(x) = 32

注意事项 #

• 完全兼容你现有所有dbg(...)调用，不需要做任何修改
• 支持参数多行书写、参数带嵌套函数/括号、字符串参数等场景
• 调试关闭时切换为空函数即可，无任何额外性能开销

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