需要讀取的文件內(nèi)容：http://python.itcarlow.ie/chapter3/sketch.txt

1. 切換工作目錄

代碼：

import os
os.chdir('D:/')    # 注意斜杠方向
print(os.getcwd())

輸出：

D:\

2. 打開文件open()

代碼：

try:
    data = open('sketch.txt')
    print(data.readline(), end='')    # 讀取一行內(nèi)容
    print(data.readline(), end='')    # 讀取二行內(nèi)容
    data.seek(0)    # 返回文件起始位置
except IOError:
    print('The data file is missing!')

輸出：

Man: Is this the right room for an argument?
Other Man: I've told you once.
0

3. 輸出所有內(nèi)容

代碼：

for each_line in data:
    try:
        (role, line_spoken) = each_line.split(':', 1)
        print(role, end='')
        print(' said: ', end='')
        print(line_spoken, end='')
    except ValueError:    # 因?yàn)閿?shù)據(jù)中存在多個冒號和沒有冒號的數(shù)據(jù)，需要處理產(chǎn)生的錯誤，
        print(each_line)

部分輸出：

Man said:  Is this the right room for an argument?
Other Man said:  I've told you once.
... ...
Man said:  (exasperated) Oh, this is futile!!
Other Man said:  No it isn't!
Man said:  Yes it is!

4. 關(guān)閉文件

代碼：

if 'data' in locals():
    data.close()

# 或者使用with打開文件，則不需要手動close：
with open('sketch.txt', 'w') as data:

5. 完整代碼

try:
    with open('sketch.txt') as data:
        for each_line in data:
            try:
                (role, line_spoken) = each_line.split(':', 1)    # split('', 1)處理多個冒號的情況，只分一次；
                print(role, end='')
                print(' said: ', end='')
                print(line_spoken, end='')
            except ValueError:    # 因?yàn)閿?shù)據(jù)中存在沒有冒號的數(shù)據(jù)，需要處理產(chǎn)生的錯誤；
                print(each_line)
except IOError as err:
    print('IOError: ' + str(err))