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我正在遍历文件以找到最高值，然后返回值和行数。如果我没有转换myMax，int()我会得到一个无序类型错误，变量设置为字符串。我忘了什么？！

def main():
    myMax= 0
    myCount = 0

    myFile = open("numbers.dat", 'r')
    for line in myFile :
        myCount = myCount + 1
        if int(line) > int(myMax): 
            myMax = line

    myFile.close()

    print ("Out of %s lines, the highest value found was %s" %(myCount, myMax))

main()
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4 回答 4

3

您需要更改myMax = line为myMax = int(line). 这也将使if int(line) > int(myMax):可转换为if int(line) > myMax:

于 2012-11-06T02:41:02.793 回答
0

如果您的“numbers.dat”文件在整个文件中包含字符串和数字，这就是我用来解决您的问题的方法。我必须逐个字符地分解行，然后将任何多位数的数字构建到字符串变量 myTemp 中，然后每当没有数字字符时，我检查 myTemp 的大小以及其中是否有任何内容将其转换为整数并将其分配给 myInt，将 myTemp 变量重置为空（因此，如果该行上有另一个数字，它将不会添加到已经存在的数字中），然后将其与当前的 Max 进行比较。这是几个如果，但我认为它可以完成工作。

def is_number(s):
try:
    float(s)
    return True
except ValueError:
    return False

定义主（）：

myMax= 0
myCount = 0
myTemp = ''
lastCharNum = False

myFile = open("numbers.dat", 'r')
for line in myFile :
    myCount = myCount + 1
    for char in line: #go through each character on the line
        if is_number(char) == False:  #if the character isnt a number
            if len(myTemp) == 0:   #if the myTemp is empty  
                lastCharNum = False #set lastchar false
                continue #then continue to the next char
            else:      #else myTemp has something in it
                myInt = int(myTemp)#turn into int
                myTemp = '' #Flush myTemp variable for next number (so it can check on same line)
                if myInt > myMax: #compare
                    myMax = myInt

        else:# otherwise the char is a num and we save it to myTemp

            if lastCharNum:
                myTemp = myTemp + char
                lastCharNum = True #sets it true for the next time around
            else:
                myTemp = char
                lastCharNum = True #sets it true for the next time around

myFile.close()

print ("Out of %s lines, the highest value found was %s" %(myCount, myMax))

主要的（）

如果“numbers.dat”文件的每一行只有数字，那么这很容易解决：

def main():
myMax= 0
myCount = 0

myFile = open("numbers.dat", 'r')
for line in myFile :
    myCount = myCount + 1
    if int(line) > myMax: #compare
        myMax = int(line)

myFile.close()

print ("Out of %s lines, the highest value found was %s" %(myCount, myMax))

主要的（）

于 2012-11-06T04:50:17.443 回答
0

您的文件包含有效数字，而不是无法转换为数字的字符串。

with open('numbers.dat') as f:
   lines = [int(line) for line in f if line.strip()]

print 'Out of %s lines, the highest value is %s' % (len(lines),max(lines))
于 2012-11-06T02:38:38.757 回答
0

我猜这行'myMax = line'导致它 - 你进行了类型转换（如果int（line）> int（myMax）:)但没有分配它。如果：

def main():
    myMax = 0
    with open("numbers.dat", 'r') as myFile:
        for i, line in enumerate((int(x) for x in myFile)):
            if line > myMax: 
                myMax = line

    print ("Out of %s lines, the highest value found was %s" % (i, myMax))

main()

如果您有空行并想跳过它们：

def main():
    myMax = 0
    with open("numbers.dat", 'r') as myFile:
        for i, line in enumerate((int(x) for x in myFile if x)):
            if line > myMax: 
                myMax = line

    print ("Out of %s lines, the highest value found was %s" % (i, myMax))

main()
于 2012-11-06T02:39:27.070 回答