文件操作

打开 操作  关闭
 r  只读
 w 只写，写前清空
 a 只能追加
 r+  读，默认从光标开始读，也可以通过seek调整光标的位置
     写，从光标所在的位子开始写，也可以通过seek调整光标的位置
 w+  读，默认光标在写的最后，也可以通过seek调整光标的位置
     写， 先清空
 a+  读，默认光标在写的最后，也可以通过seek调整光标的位置
     写，永远写到最后


############################ read only#################################
"""
#open file
file_object = open('test.txt', mode='r', encoding='utf-8') #r, read;w,write(clear all the content); a,append

#read  file
content = file_object.read()
print(content)

#close file
file_object.close()
"""

############################ write only，file new created if not exist #################################
"""
#open file
file_object = open('test.txt', mode='w', encoding='utf-8') #r, read;w,write(clear all the content); a,append

#write  file
file_object.write('change')


#close file
file_object.close()
"""
############################ append only,file new created if not exist #################################
"""
#open file
file_object = open('test.txt', mode='a', encoding='utf-8') #r, read;w,write(clear all the content); a,append

#append  file
file_object.write('添加')


#close file
file_object.close()
"""
############################## r+ #######################################
"""
#open file
file_object = open('test.txt', mode='r+', encoding='utf-8') #r, read;w,write(clear all the content); a,append

#append  file
content = file_object.read()
print(content)
file_object.write('添加')

#close file
file_object.close()
"""


############################## w+ #######################################
"""
#open file
file_object = open('test.txt', mode='w+', encoding='utf-8') #r, read;w,write(clear all the content); a,append


file_object.write('添加')
file_object.seek(0) # 调整光标位置 到开始位置
content = file_object.read()
print(content)

#close file
file_object.close()
"""

############################## a+ #######################################
"""
#open file
file_object = open('test.txt', mode='a+', encoding='utf-8') 


file_object.write('添加')
file_object.seek(0) # 调整光标位置 到开始位置
content = file_object.read()
print(content)

#close file
file_object.close()
"""