Question

我循环浏览文件以找到最高值，然后返回值和行数。如果我没有用myMax转换int()，我会得到一个无序类型错误，变量设置为字符串。我忘记了什么？！

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()

Answer 1

您需要将myMax = line更改为myMax = int(line)。这也会使if int(line) > int(myMax):转换为if int(line) > myMax:

Answer 2

此文件包含有效数字，而不包含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))

Answer 3

我想'myMax = line'这一行导致它 - 你进行了类型转换（如果是int（line）＆gt; int（myMax）:)但是没有分配它。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()

Answer 4

如果您的“numbers.dat”文件在整个文件中包含字符串和数字，那么这就是我用来解决问题的方法。我不得不逐个字符地分解行，然后将多个数字的数字构建到字符串变量myTemp中，然后每当没有字符的数字时，我检查myTemp的大小以及是否有任何内容将它变成一个整数并将其分配给myInt，将myTemp变量重置为空（如果行上有另一个数字，它将不会添加到已存在的数字），然后将其与当前的Max进行比较。这是几个ifs，但我认为它可以做到这一点。

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

def main（）：

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))

main（）

如果“numbers.dat”文件每行只有数字，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))

main（）

无序类型错误：int存储为字符串

4 个答案: