Question

我的简单任务是编写一个要求输入文件名的函数，然后重复读取用户的行并将这些行保存到指定的文件中。

当用户输入本身就是一个点上时，它会停止保存行。不保存包含单个点的行。

示例输出如下：

Save to what file: mytest.txt
> This is
> my attempt at
> the problem.
>
> The last line was empty
> .
Saving file mytest.txt
5 lines saved

这是我的尝试：

def savefile():
    filename = input("Save to what file: ")
    infile = open(filename, "w")
    line = ""
    lineCount = 0
    while line != ".":
        line = input("> ")
        infile.write(line + "\n")
        lineCount += 1


    print("Saving file", filename)
    print(lineCount, "lines saved")

    infile.close()

工作正常，但我的while循环也保存了最后一行（＆＃34;。＆＃34;单独在一行上）。我还尝试了if - else循环：

if line != ".":
    line = input("> ")
    infile.write(line + "\n")
    lineCount += 1
else:
    infile.close()

但这只是保存输入的第一行。

如何排除输入的最后一行？

Answer 1

甚至不需要解释：

with open("my_file.txt","w") as file:
    while True:
        line = input("> ")
        if line.strip() == ".":
            break
        else:
            file.write(line + "\n")

Answer 2

您可以通过简单地在代码中交换一些行来尝试这一点，如下所示：

def savefile():
    filename = input("Save to what file: ")
    infile = open(filename, "w")
    line = input("> ")
    lineCount = 0
    while line != ".":
        infile.write(line + "\n")
        lineCount += 1
        line = input("> ")


    print("Saving file", filename)
    print(lineCount, "lines saved")

    infile.close()

Answer 3

这只是有点乱，经典问题，将输入移到while循环上面，我希望看到原因......

def savefile():
    filename = input("Save to what file: ")
    infile = open(filename, "w")
    line = ""
    lineCount = 0
    # first lets get the line of input
    line = input("> ")
    # if the line is "." then don't do the following code.
    while line != ".":
        # if the line was not "." then we do this...
        infile.write(line + "\n")
        lineCount += 1
        # get the input again, and loop, remember if we get "."
        # we will break from this loop.
        line = input("> ")


    print("Saving file", filename)
    print(lineCount, "lines saved")

    infile.close()

将输入写入文件，不包括最后一行

3 个答案: