python之在 Python 中使用 for 循环读取文件内容

问题来了。我有 names.txt 文件。该文件的内容如下。该问题要求显示此文件中的名称数量。我可以使用 while 循环。它有效，没问题。但出于某种原因，如果我想用 for 循环执行此操作，它会给我错误的名称数。

    Julia Roberts  
    Michael Scott 
    Kevin Malone 
    Jim Halpert 
    Pam Halpert 
    Dwight Schrute 

这是 while 循环。它运行完美。

def main(): 
    try: 
        # open the names.txt file in read mode. 
        infile=open("names.txt", "r") 
 
        # set an accumulator for number of names 
        numbers_of_name=0.0 
 
        # read the first line 
        line=infile.readline() 
 
        # read the rest of the file 
        while line!="": 
            numbers_of_name+=1 
            line=infile.readline() 
 
        # print the numbers of names in the names.txt file.     
        print("There are", int(numbers_of_name), "names in the names.txt file.") 
 
        # close the file 
        infile.close() 
    except IOError as err: 
        print (err)  
 
# call the main function 
main() 

控制台给了我正确的答案。

There are 6 names in the names.txt file. 

这是我有问题的 for 循环

def main(): 
    try: 
        # open the names.txt file in read mode. 
        infile=open("names.txt", "r") 
 
        # set an accumulator for number of names 
        numbers_of_name=0.0 
 
        # read the rest of the file 
        for line in infile: 
            line=infile.readline() 
            numbers_of_name+=1 
 
        # print the numbers of names in the names.txt file.     
        print("There are ", numbers_of_name, "names in the names.txt file.") 
 
        # close the file 
        infile.close() 
    except IOError as err: 
        print (err)  
 
# call the main function 
main() 

这是输出。

There are  3.0 names in the names.txt file.  

应该有 6 个名字而不是 3 个名字。:

此文件读取代码中可能缺少什么部分？提前致谢。

请您参考如下方法:

问题是你在每次迭代中读取两行，当你这样做时:

for line in infile: 

行是文件中的第一行，当你这样做时:

line.readline() 

然后一行现在是第二行，然后你加一二你的名字计数

你应该这样做:

for line in infile: 
    numbers_of_name+=1