一、写入空文件（覆盖）

# coding=UTF-8
filename = 'test_text.txt'
with open(filename, 'w') as file_object:
    file_object.write("Add a word")

如果写入文件不存在，open（）将自动创建它

如果文件已存在已有内容，会清空再写入

写入多行

# coding=UTF-8
filename = 'test_text.txt'
with open(filename, 'w') as file_object:
    file_object.write("Add a word")
    file_object.write("Add two words")

加换行符

# coding=UTF-8
filename = 'test_text.txt'
with open(filename, 'w') as file_object:
    file_object.write("Add a word\n")
    file_object.write("Add two words\n")

二、在原有文件上添加内容

用‘a’

# coding=UTF-8
filename = 'test_text.txt'
with open(filename, 'a') as file_object:
    file_object.write("lalala\n")
    file_object.write("hahaha\n")