我做错了什么？Python阅读与识别

编写一个程序，读取名为“distance.txt”的输入文件，格式如下：

John Smith 5 mi  
Mary Jones 8 km  
Jack Washington 3.8 mi  
Jill Adams 9.1 km 

您的程序应该将距离最远的人的全名输出到名为“winner.txt”的文件中

到目前为止我所拥有的

def read(fileName):
    list2 =[]  
    infile = open(fileName, "r")
    for line in infile:
        words = line.split()
        words[2] = float(words[2])
        if words[3] == "mi":
            words[2] = words[2] / 0.62137
            words[3] = "km"
            words[2] = float("{0:.1f}".format(words[2]))
        else:
            pass
        list2.append(words[2])
    maximum = max(list2)
    infile.close()
return

def rinter(fileName, maximum):
    infile = open(fileName, "r")
    for line in infile:
        if maximum in line:
            print(line)

    fileName = read("distances.txt")
    newcode = rinter(fileName,maximum)

    print(fileName)

---

请注意，函数中的变量具有局部作用域，您需要在

read

函数中返回

最大值

，然后将其作为

rinter

函数的参数：

def read(fileName):
    list2 =[]  
    infile = open(fileName, "r")
    for line in infile:
        words = line.split()
        words[2] = float(words[2])
        if words[3] == "mi":
            words[2] = words[2] / 0.62137
            words[3] = "km"
            words[2] = float("{0:.1f}".format(words[2]))
        else:
            pass
        list2.append(words[2])
    maximum = max(list2)
    infile.close()
    return maximum


def rinter(fileName, maximum):
    infile = open(fileName, "r")
    for line in infile:
        if maximum in line:
             print(line)

maximum = read("distances.txt")
newcode = rinter("winner.txt",maximum)

def read(fileName):
    list2 =[]  
    infile = open(fileName, "r")
    for line in infile:
        words = line.split()
        words[2] = float(words[2])
        if words[3] == "mi":
            words[2] = words[2] / 0.62137
            words[3] = "km"
            words[2] = float("{0:.1f}".format(words[2]))
        else:
            pass
        list2.append(words[:2])
    maximum = max(list2,key=lambda x:x[2])
    infile.close()
    return maximum


def rinter(fileName, maximum):
    infile = open(fileName, "r")
    infile.write(' '.join(maximum))
    print('winner is :'+' '.join(maximum))

maximum = read("distances.txt")
newcode = rinter("winner.txt",maximum)

但这段代码只需将距离添加到

winner

文件，如果需要添加全名，则需要使用另一种算法，您需要保存一个拆分的行列表，但从第一行切片到索引2，然后查找最大使用

max

函数，其

键为lambda函数，该函数根据第2个索引查找最大值！然后，为了将其写入文件，请使用
join
函数连接索引：

def read(fileName):
    list2 =[]  
    infile = open(fileName, "r")
    for line in infile:
        words = line.split()
        words[2] = float(words[2])
        if words[3] == "mi":
            words[2] = words[2] / 0.62137
            words[3] = "km"
            words[2] = float("{0:.1f}".format(words[2]))
        else:
            pass
        list2.append(words[2])
    maximum = max(list2)
    infile.close()
    return maximum


def rinter(fileName, maximum):
    infile = open(fileName, "r")
    for line in infile:
        if maximum in line:
             print(line)

maximum = read("distances.txt")
newcode = rinter("winner.txt",maximum)

def read(fileName):
    list2 =[]  
    infile = open(fileName, "r")
    for line in infile:
        words = line.split()
        words[2] = float(words[2])
        if words[3] == "mi":
            words[2] = words[2] / 0.62137
            words[3] = "km"
            words[2] = float("{0:.1f}".format(words[2]))
        else:
            pass
        list2.append(words[:2])
    maximum = max(list2,key=lambda x:x[2])
    infile.close()
    return maximum


def rinter(fileName, maximum):
    infile = open(fileName, "r")
    infile.write(' '.join(maximum))
    print('winner is :'+' '.join(maximum))

maximum = read("distances.txt")
newcode = rinter("winner.txt",maximum)

如果您不想使用
lambda
（如您在评论中所说），可以使用列表理解：
因此，请替换以下行：

maximum = max(list2,key=lambda x:x[2])

与：

maximum = [l for l in list2 if l[2]==max(zip(*list2)[2])][0]

zip（*list2）
为您提供
list2的列列表
因此
zip（*list2）[2]
是距离列表，然后
max（zip（*list2）[2]）
是在选择最大列表的条件下使用它的最大距离！最后一个
[0]
是因为上面代码的结果是一个带有一个索引的嵌套列表
[[]]
，您需要内部列表！但我不建议将
max
函数与
lambda
一起使用，该函数具有更高的性能，并且更pythonic
您可能需要将字符串转换为两倍：

words[2] = words[2] / 0.62137

您必须返回最大值或将其声明为全局变量。
我修复了读取函数。现在它返回人名及其距离：

def read(fileName):
    list2 =[]
    infile = open(fileName, "r")
    for line in infile:
        words = line.split()
        #print(words)
        words[2] = float(words[2])
        if words[3] == "mi":
            words[2] = words[2] / 0.62137
            words[3] = "km"
            words[2] = float("{0:.1f}".format(words[2]))
        else:
            pass
        list2.append((' '.join(words[0:2]), words[2]))
    maximum = max(list2, key=lambda v: v[1])
    #print(list2, maximum)
    infile.close()
    return maximum

person_name, distance = read("data.csv")
print(person_name, distance)
#Jill Adams 9.1

但不确定打印机应该执行什么功能

要将结果保存在输出文件中，您可以：

with open("winner.txt", 'w') as f:
    f.write(person_name + ' ' + str(distance))

对代码的一些更改：

list1 = []       # contain names
list2 = []       # contain distance
def read(fileName):
    infile = open(fileName, "r")
    for line in infile:
        words = line.split()
        list1.append(" ".join(words[0:2]))
        words[2] = float(words[2])
        if words[3] == "mi":
            words[2] = words[2] / 0.62137
            list2.append(float(words[2]))
       else:
           list2.append(float(words[2]))

    infile.close()
read("distances.txt")
maximum = max(list2)
winner = list1[list2.index(maximum)]
print(winner,maximum,"km")
f = open('winner.txt','w')
f.write(winner+" "+ str(mamimum)+" km")
f.close()

那么问题是什么呢？有错误吗？我只得到第一个函数，没有返回任何内容else@Slowtailes我编辑了答案并添加了一个完整的答案，你可以查看它，@Kasra没有lambda函数我有什么办法可以做到吗？我对他们不太熟悉是的，你可以使用列表理解，我会很快添加到答案中！这个如何返回人的全名，并编写输出文件？@Marcin我只是想改进那个OP想要做的事情，我错过了这个问题，我将编辑答案！谢谢提醒