Python读写txt文件时get_min函数报错‘l不可读’求助

你的代码中get_min函数报错的核心原因是：函数定义时声明接收参数l，但函数内部却试图调用外部的nums变量——这个变量仅存在于循环的作用域内，函数内部无法访问，因此抛出了找不到变量的错误。

修正方案 #

只需要将get_min函数内的nums替换为参数l，和get_max、get_avg保持一致的参数使用逻辑即可：

in_file = open("input.txt", "r")
out_file = open("output.txt", "w")

def get_min(l):
    return min(l)  # 将原代码的nums改为函数参数l

def get_max(l):
    return max(l)

def get_avg(l):
    return sum(l) / len(l)

for line in in_file:
    parts = line.split(":")
    cmd = parts[0].strip().lower()
    nums = parts[1].strip().split(",")
    for i in range(len(nums)):
        nums[i] = int(nums[i])
    
    if cmd == "min":
        out_file.write("The min of [" + ", ".join([str(i) for i in nums]) + "] is " + str(get_min(nums)) + "\n")
    elif cmd == "max":
        out_file.write("The max of [" + ", ".join([str(i) for i in nums]) + "] is " + str(get_max(nums)) + "\n")
    elif cmd == "avg":
        out_file.write("The avg of [" + ", ".join([str(i) for i in nums]) + "] is " + str(get_avg(nums)) + "\n")  # 补充换行符，保持输出格式统一

in_file.close()
out_file.close()

额外优化建议 #

可以使用Python的with语句管理文件操作，它会自动处理文件的关闭逻辑，避免手动关闭可能出现的遗漏：

def get_min(l):
    return min(l)

def get_max(l):
    return max(l)

def get_avg(l):
    return sum(l) / len(l)

with open("input.txt", "r") as in_file, open("output.txt", "w") as out_file:
    for line in in_file:
        parts = line.split(":")
        cmd = parts[0].strip().lower()
        nums = list(map(int, parts[1].strip().split(",")))  # 用map简化类型转换
        
        if cmd == "min":
            out_file.write(f"The min of [{', '.join(map(str, nums))}] is {get_min(nums)}.\n")
        elif cmd == "max":
            out_file.write(f"The max of [{', '.join(map(str, nums))}] is {get_max(nums)}.\n")
        elif cmd == "avg":
            out_file.write(f"The avg of [{', '.join(map(str, nums))}] is {get_avg(nums)}.\n")

内容的提问来源于stack exchange，提问作者Miwok