文件的基本方法以及对内容的迭代

# 文件的基本方法以及对内容的迭代
# 1.open,write and read
>>> f = open(r'E:\code\py\file\test.txt','w')
>>> f.write('hello, ')
7
>>> f.write('world')
5
>>> f.close()
>>> f = open(r'E:\code\py\file\test.txt','r')
>>> f.read(4)
'hell'
>>> f.read()
'o, world'
>>> f.read()
''
>>> f.close()
>>> f = open(r'E:\code\py\file\test.txt')
>>> f.read()
'hello, world'
>>> f.close()
>>> f = open(r'E:\code\py\file\test.txt','w')
>>> f.write('hello,huhu')
10
>>> f.close()
>>> f = open(r'E:\code\py\file\test.txt')
>>> f.read()
'hello,huhu'
>>> f.close()

# 2.seek and tell
>>> f = open(r'E:\code\py\file\test.txt','w')
>>> f.write('0123456789')
10
>>> f.seek(5)
5
>>> f.write('hello,huhu')
10
>>> f.close()
>>> f = open(r'E:\code\py\file\test.txt')
>>> f.read()
'01234hello,huhu'
>>> f.close()

>>> f = open(r'E:\code\py\file\test.txt')
>>> f.read(4)
'0123'
>>> f.seek(3)
3
>>> f.read()
'34hello,huhu'
>>> f.tell()
15
>>> f.seek(5)
5
>>> f.tell()
5
>>> f.read(4)
'hell'
>>> f.tell()
9

# 3.with statement
>>> with open(r'E:\code\py\file\test.txt','w') as f:
    f.write('hello, 1234567890')

    
17
>>> with open(r'E:\code\py\file\test.txt','r') as f:
    f.read()

    
'hello, 1234567890'

# 4.write, writelines
>>> f = open(r'E:\code\py\file\test.txt','w')
>>> f.write('Welcome to this file\nThere is nothing here except\nThis stupid haiku\n')
68
>>> f.close()

>>> with open(r'E:\code\py\file\test.txt','w') as f:
    for i in l:
        f.write(i)

        
21
29
18

>>> with open(r'E:\code\py\file\test.txt','w') as f:
    f.writelines(l)


# 5.read,readline and readlines
# 5.1 read(n) and read()
>>> f = open(r'E:\code\py\file\test.txt')
>>> f.read(7)
'Welcome'
>>> f.read(5)
' to t'
>>> f.read()
'his file\nThere is nothing here except\nThis stupid haiku\n'
>>> f.close()

>>> f = open(r'E:\code\py\file\test.txt')
>>> f.read()
'Welcome to this file\nThere is nothing here except\nThis stupid haiku\n'
>>> f.read()
''
>>> f.close()

>>> f = open(r'E:\code\py\file\test.txt')
>>> print(f.read())
Welcome to this file
There is nothing here except
This stupid haiku

>>> f.close()

# 按照字节遍历文件内容
>>> f = open(r'E:\code\py\file\test.txt')
>>> while True:
    c = f.read(1)
    if len(c) == 0:
        break
    print(c, end = '')

    
Welcome to this file
There is nothing here except
This stupid haiku
>>> f.close()

# 读取所有内容（整个文件当做一个字符串）
# 1
>>> with open(r'E:\code\py\file\test.txt') as f:
    while True:
        line = f.read()
        if len(line) == 0:
            break
        print(line)

        
Welcome to this file
There is nothing here except
This stupid haiku

>>> 
# 2
>>> with open(r'E:\code\py\file\test.txt') as f:
    for c in f.read():
        print(c, end = '')

        
Welcome to this file
There is nothing here except
This stupid haiku
>>> 

# 5.2 f.readline()
>>> f = open(r'E:\code\py\file\test.txt')
>>> f.readline()
'Welcome to this file\n'
>>> f.readline()
'There is nothing here except\n'
>>> f.readline()
'This stupid haiku\n'
>>> f.readline()
''
>>> f.close()

# 按照行遍历文件内容
>>> with open(r'E:\code\py\file\test.txt') as f:
    while True:
        line = f.readline()
        if len(line) == 0:
            break
        print(line)

        
Welcome to this file

There is nothing here except

This stupid haiku

>>> 

>>> with open(r'E:\code\py\file\test.txt') as f:
    while True:
        line = f.readline()
        if len(line) == 0:
            break
        print(line, end = '')

        
Welcome to this file
There is nothing here except
This stupid haiku
>>> 

#5.3 readlines()
>>> f = open(r'E:\code\py\file\test.txt')
>>> f.readlines()
['Welcome to this file\n', 'There is nothing here except\n', 'This stupid haiku\n']
>>> f.readlines()
[]
>>> f.close()

>>> f = open(r'E:\code\py\file\test.txt')
>>> import pprint
>>> pprint.pprint(f.readlines())
['Welcome to this file\n',
 'There is nothing here except\n',
 'This stupid haiku\n']
>>> f.close()

# 读取所有内容（整个文件当做一个字符串列表）
>>> with open(r'E:\code\py\file\test.txt') as f:
    for line in f.readlines():
        print(line)

        
Welcome to this file

There is nothing here except

This stupid haiku

>>> with open(r'E:\code\py\file\test.txt') as f:
    for line in f.readlines():
        print(line, end = '')

        
Welcome to this file
There is nothing here except
This stupid haiku
>>>