这是我的个人文件类;-)
class File(file):
""" An helper class for file reading """
def __init__(self, *args, **kwargs):
super(File, self).__init__(*args, **kwargs)
self.BLOCKSIZE = 4096
def head(self, lines_2find=1):
self.seek(0) #Rewind file
return [super(File, self).next() for x in xrange(lines_2find)]
def tail(self, lines_2find=1):
self.seek(0, 2) #Go to end of file
bytes_in_file = self.tell()
lines_found, total_bytes_scanned = 0, 0
while (lines_2find + 1 > lines_found and
bytes_in_file > total_bytes_scanned):
byte_block = min(
self.BLOCKSIZE,
bytes_in_file - total_bytes_scanned)
self.seek( -(byte_block + total_bytes_scanned), 2)
total_bytes_scanned += byte_block
lines_found += self.read(self.BLOCKSIZE).count('\n')
self.seek(-total_bytes_scanned, 2)
line_list = list(self.readlines())
return line_list[-lines_2find:]
def backward(self):
self.seek(0, 2) #Go to end of file
blocksize = self.BLOCKSIZE
last_row = ''
while self.tell() != 0:
try:
self.seek(-blocksize, 1)
except IOError:
blocksize = self.tell()
self.seek(-blocksize, 1)
block = self.read(blocksize)
self.seek(-blocksize, 1)
rows = block.split('\n')
rows[-1] = rows[-1] + last_row
while rows:
last_row = rows.pop(-1)
if rows and last_row:
yield last_row
yield last_row
用法示例：
with File('file.name') as f:
print f.head(5)
print f.tail(5)
for row in f.backward():
print row
602392714
清零编程群