python如何将字符串等长分割

#!/bin/python 
#site:WWW.jb51.net
# 
A = open('mac.txt','r') 
a = A.readlines() 
for aa in a: 
 b = list(aa.strip()) 
 c='' 
 for i in range(len(b)): 
  if i !=0: 
   if i%2 == 0: 
    c=c+'-'+b[i] 
   else: 
    c=c+b[i] 
  else: 
   c=c+b[i] 
 print c 
A.close()

#!/bin/python 
# 
import re 
A = open('mac.txt','r') 
a = A.readlines() 
for aa in a: 
 b=re.findall(r'.{2}',aa) 
 c='-'.join(b) 
 print c 
A.close()

def cut_text(text,lenth): 
 textArr = re.findall('.{'+str(lenth)+'}', text) 
 textArr.append(text[(len(textArr)*lenth):]) 
 return textArr 
  
print(cut_text('123456789abcdefg',3)) 
  
['123', '456', '789', 'abc', 'def', 'g']

>>> import re
>>> string = '123456789abcdefg'
>>> re.findall(r'.{3}', string)
['123', '456', '789', 'abc', 'def']
>>>