Python 文件行数读取的三种方法

Python三种文件行数读取的方法：

#文件比较小
count = len(open(r"d:\lines_test.txt",'rU').readlines())
print count
 
#文件比较大
count = -1
 
for count,line in enumerate(open(r"d:\lines_test.txt",'rU')):
pass
count += 1
 
print count
 
#更好的方法
count = 0
 
thefile = open(r"d:\lines_test.txt",'rb')
 
while True:
buffer = thefile.read(1024 * 8192)
if not buffer:
break
count += buffer.count('\n')
thefile.close()
 
print count