Python3读取文件常用方法实例分析

''''' 
Created on Dec 17,2012 
读取文件 
@author: liury_lab 
''' 
# 最方便的方法是一次性读取文件中的所有内容放到一个大字符串中： 
all_the_text = open('d:/text.txt').read() 
print(all_the_text) 
all_the_data = open('d:/data.txt','rb').read() 
print(all_the_data) 
# 更规范的方法 
file_object = open('d:/text.txt') 
try: 
  all_the_text = file_object.read() 
  print(all_the_text) 
finally: 
  file_object.close() 
# 下面的方法每行后面有‘n'  
file_object = open('d:/text.txt') 
try: 
  all_the_text = file_object.readlines() 
  print(all_the_text) 
finally: 
  file_object.close() 
# 三句都可将末尾的'n'去掉  
file_object = open('d:/text.txt') 
try: 
  #all_the_text = file_object.read().splitlines() 
  #all_the_text = file_object.read().split('n') 
  all_the_text = [L.rstrip('n') for L in file_object] 
  print(all_the_text) 
finally: 
  file_object.close() 
# 逐行读 
file_object = open('d:/text.txt') 
try: 
  for line in file_object: 
    print(line,end = '') 
finally: 
  file_object.close() 
# 每次读取文件的一部分 
def read_file_by_chunks(file_name,chunk_size = 100):   
  file_object = open(file_name,'rb') 
  while True: 
    chunk = file_object.read(chunk_size) 
    if not chunk: 
      break 
    yield chunk 
  file_object.close() 
for chunk in read_file_by_chunks('d:/data.txt',4): 
  print(chunk)

hello python
hello world
b'ABCDEFGrnHELLOrnhello'
hello python
hello world
['hello pythonn','hello world']
['hello python','hello world']
hello python
hello worldb'ABCD'
b'EFGr'
b'nHEL'
b'LOrn'
b'hell'
b'o'