python提取具有某种特定字符串的行数据方法

#coding:utf-8
#__author__ ='dell'

import re

f1=file('losstotal.txt','r')
data1=f1.readlines()
# print data1
f1.close()
results = []
f2 = open('loss2.txt', 'w')

# # 按照特定行提取，发现后面的行并无规律
# i = 0
# for line in data1:
# i+=1
# # print line
# if((i-1)%3==0):
# f2.write(line)
# print line


# 利用正则表达式

for line in data1:
 data2=line.split()
 # print data2
 for i in data2:
 n = re.findall(r"Iteration", i)
 # m=re.findall(r"loss", i)
 if n:
  # print line
  f2.writelines(line)
f2.close()


f3=file('loss2.txt','r')
data3=f3.readlines()
# print data1
f3.close()
f4 = open('loss3.txt', 'w')

for line in data3:
 data4=line.split()
 # print data2
 for i in data4:
 n = re.findall(r"loss", i)
 # m=re.findall(r"loss", i)
 if n:
  print line
  f4.writelines(line)
f4.close()


# 去掉逗号
f5=open('loss3.txt','r')
data5=f5.read()
f5=data5.replace(',',' ')
f6=file('lossfinal.txt','w')
f6.write(f5)
f6.close()

# # 去掉等号=
f7=open('lossfinal.txt','r')
data7=f7.read()
f7=data7.replace('=',' ')
f8=file('lossfinal.txt','w')
f8.write(f7)
f8.close()
  # data3=lin.split()
  # for j in data3:
  # m=re.findall(r"loss",i)
  # if m:
  # print lin

 # # m=re.findall(r"sgd_solver.cpp",i)
 # n=re.findall(r"Iteration",i)