Question

我正在尝试将以下代码打印到文件中。查看堆栈溢出时，我发现了file = open代码，但它似乎没有写入文件。

PS。我还没有创建文件

print("Average Grade " + str(average), "At least 70% " + 
      str(Grade1), "60% - 69% " + str(Grade2), "50% - 59% " +
      str(Grade3), "40% - 49% " + str(Grade4), "Less than 40% " + 
      str(Grade5), "Highest Grade " +
      str(max_grade), "Student Name:" + str(student_name), sep="\n", 
      file=open("results.txt", 'a'))

Answer 1

在python中，我们通常不使用print语句执行此操作。考虑以下替代方案。使用“上下文管理器”可以编写多行内容，并且还可以避免某些问题，如果程序在写入文件时抛出错误。

with open('results.txt', 'a') as f:
    line = "Average Grade " + str(average), "At least 70% " + str(Grade1), "60% - 69% " + str(Grade2), "50% - 59% " + str(Grade3), "40% - 49% " + str(Grade4), "Less than 40% " + str(Grade5), "Highest Grade " + str(max_grade), "Student Name:" + str(student_name)
    f.write(line)

顺便说一句，如果以交互方式执行此操作，则可能不会立即看到写入文件的数据-使用终端而不是运行脚本时，这可能是真正的困惑！发生的事情是python将数据大块地写入文件，而不是每次调用f.write时都要求硬盘驱动器工作。 flush输出缓冲区告诉python立即写入数据，例如f.flush()。

print语句实际上确实有一个flush参数，因此可能与该参数高度相关。不过，我还是建议使用with语句。

Answer 2

with open("results.txt", 'a') as f:
    f.write("Average Grade " + str(average), "At least 70% " + 
    str(Grade1), "60% - 69% " + str(Grade2), "50% - 59% " +
    str(Grade3), "40% - 49% " + str(Grade4), "Less than 40% " + 
    str(Grade5), "Highest Grade " +
    str(max_grade), "Student Name:" + str(student_name))

请注意，打开的'a'选项用于附加。您还可以使用“ w”进行写入。

Answer 3

我明白了。我打开文件，然后在打印结束时使用file =。

newFile = open("results.txt", 'w')

print("Average Grade " + str(average), "At least 70% " + str(Grade1), "60% - 69% " + str(Grade2), "50% - 59% " +
  str(Grade3), "40% - 49% " + str(Grade4), "Less than 40% " + str(Grade5), "Highest Grade " +
  str(max_grade), "Student Name:" + str(student_name), sep="\n", file=newFile)

newFile.close()

Answer 4

尝试一下：

lxml

在open =下使用print

4 个答案: