Python 文件

首先申明下，本文为笔者学习《Python学习手册》的笔记，并加入笔者自己的理解和归纳总结。

1、打开文件

>>> input = open('data', "r") 字符串"r"代表读取文件。 字符串"w"代表写入文件 字符串"a"代表写入文件末尾。 字符串"b"代表文件是二进制文件

2、读写操作

(1) write()方法 >>> filePath = "myfile.txt" >>> output = open(filePath, "w") # 打开文件 >>> output.write("Hello World!\n") # 输入内容 >>> output.write("Welcome to Python\n") >>> output.write("Nice to meet you") >>> output.close() # 关闭文件 (2) read()方法 >>> input = open(filePath, "r") >>> input.read() # 读取所有内容，返回一个字符串 'Hello World!\nWelcome to Python\nNice to meet you' (3) readlines()方法 >>> input = open(filePath, "r") >>> input.readlines() # 读取所有内容，返回字符串列表 ['Hello World!\n', 'Welcome to Python\n', 'Nice to meet you'] (4) readline()方法 >>> input = open(filePath, "r") >>> input.readline() # 读取一行字符串 'Hello World!\n' >>> input.readline() 'Welcome to Python\n' >>> input.readline() 'Nice to meet you' >>> input.readline() # 文件末尾返回空字符串 '' (5) for函数 >>> for line in open(filePath, "r"): # 文件迭代 print line.rstrip(), Hello World! Welcome to Python Nice to meet you

3、pickle模块

(1) pickle模块用来存储Python对象。 >>> L = ["Hello", "World"] >>> D = {"name":"Jack", "age":18} >>> filePath = "mydata.pkl" >>> output = open(filePath, "wb") # 文件类型是二进制 >>> import pickle >>> pickle.dump(L, output) # dump方法输入列表对象 >>> pickle.dump(D, output) # dump方法输入字典对象 >>> output.close() (2) pickle模块读取存储Python对象。 >>> input = open(filePath, "rb") >>> import pickle >>> pickle.load(input) # load方法读取列表对象 ['Hello', 'World'] >>> pickle.load(input) # load方法读取字典对象 {'age': 18, 'name': 'Jack'}

4、shelve模块

(1) shelve模块存储Python对象 >>> L = ["Hello", "World"] >>> D = {"name":"Jack", "age":18} >>> import shelve >>> db = shelve.open("datadb") >>> db["list"] = L >>> db["dict"] = D >>> db.close() (2) shelve模块读取存储Python对象。 >>> db = shelve.open("datadb") >>> for key in db: print key, "=", db[key] dict = {'age': 18, 'name': 'Jack'} list = ['Hello', 'World']