使用带有 open= 的打印

Question

我正在尝试将以下代码打印到文件中。通过堆栈溢出，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

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，open 中的 'a' 选项用于追加。您也可以使用 'w' 进行写入。

Answer 2

在python中，我们通常不使用打印语句来执行此操作。考虑以下替代方案。使用 "context manager" 允许您写入多行，如果程序在写入文件时抛出错误，也有助于避免某些问题。

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，如果您以交互方式执行此操作，您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，这可能是一个真正的混淆点！发生的情况是 python 以大块的形式将数据写入文件，而不是每次调用 f.write 时都要求硬盘驱动器工作。 flushing 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，因此可能与此高度相关。尽管如此，我还是建议改用 with 语句。

Answer 3

我让它工作了。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

试试这个：

file = open("Here you put your path to a file, but replace '\' with '\'", 'w+')
# That opened your file in 'write' mode, and '+' means that if it does not 
# exist, one will be created
file.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))
file.close()

使用带有 open= 的打印

Using print with open=

python

file-io

python-3.x