python - 在同一脚本中读取和写入

Question

我目前正在进行艰难学习 Python 中的练习 16，我的代码在写入文件时遇到问题，但我的最终打印命令不打印内容将文件拖到控制台上。在我的命令行上，它只是出现了几行空格。据我了解，“r+”以读写模式打开它，但计算机无法读取它。 有人可以告诉我有什么问题吗？任何帮助将不胜感激:)

    from sys import argv
    script, file = argv

    print "The name of the file is %s" % file
    filename = open(file,"r+")

    print "First we must write something in it "
    print "Do you want to continue?Press CTRL-C if not."
    raw_input()

    print "Type the first line of the text"
    line1 = raw_input(">")+"\n"

    print "Type the second line of text"
    line2 = raw_input(">")+"\n"

    print "Type the third line of text"
    line3 = raw_input(">")+"\n"

    sum_line = line1 + line2 + line3

    print "Now I will write it to the file"
    filename.write(sum_line)

    print "The file now says:"

    #This line here does not print the contents of the file
    print filename.read()

    filename.close()

Answer 1

正如第一个答案中所包含的那样，写入后偏移量将指向文件末尾。但是，您不需要关闭该文件并重新打开它。最好在阅读之前执行此操作:

filename.seek(0)

这将重置文件开头的偏移量。

然后简单地阅读它。

 filename.read()