python - 在 python 3.4 上逐行读取文本文件

Question

我将一本书保存为我的 python 上的文本文件，我试图逐行读取该文件。我试过用这个

def print_file1(filename):
    f = open(filename, 't')
    for line in f:
        print(line, end = '')
    f.close() #optional

但是，每次我尝试运行它时，它都不起作用。 这就是我得到的输出

runfile('/Users/kareemahokunlola/example.py', wdir='/Users/kareemahokunlola')

Answer 1

'' 本身不是打开文件的有效模式。

您可以将模式指定为 rt。如果您省略模式，它将默认为 'r'(以文本模式阅读)，这可能足以满足您的目的。 (如果您的文件包含二进制数据，您可以将 'b' 添加到模式。)

我也会考虑用 with 语句这样写:

def print_file1(filename):
    with open(filename) as f:
        for line in f:
            print(line, end = '')

这样做的好处是您无需担心关闭文件 - 无论出于何种原因，它都会在 with 语句退出时自动发生。

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更新

那么您是从 Spyder IDE 中执行这段代码的吗？当您成功运行脚本时，Spyder 将显示:

runfile('/Users/kareemahokunlola/example.py', wdir='/Users/kareemahokunlola')

in the console. This is what you are seeing, so your script is running without error.

There are a couple of possibile explanations:

1. You are not calling the function print_file1() from within your script. The script runs without error, but the file is not displayed because print_file1() is not called. This is the most likely explanation because your original code that attempts to open the file with mode 't' will raise an exception, and that exception will be logged to the console. But the error is not displayed, hence it is probable that the function is not actually called.
2. You are calling print_file1() but the file is empty. In this case the "runfile()" message will be displayed because the script ran successfully, but nothing else is seen because the file is empty.

Try adding a call to print_file1() after you define the function:

def print_file1(filename):
    with open(filename) as f:
        for line in f:
            print(line, end = '')

# N.B. call the function...
print_file1('/etc/hosts')