在Python中使用for循环读取文件的内容

Question

这是问题所在.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循环这样做,它会给我错误的名字数量.

    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.

这是我的循环问题

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:

在这个文件阅读代码中可能缺少什么？提前致谢.

Answer 1

问题是你在每次迭代中读取两行,当你这样做时:

for line in infile:

line是文件中的第一行,当你这样做时:

line.readline()

然后行现在是第二行,然后你添加一个你的名字计数

你应该做:

for line in infile:
    numbers_of_name+=1