python3.4.3下逐行读入txt文本并去重的方法

#!/bin/python3

original_list1=[" "]

original_list2=[" "]

original_list3=[" "]

original_list4=[" "]

newlist1=[" "]

newlist2=[" "]

newlist3=[" "]

newlist4=[" "]

newtxt1=""

newtxt2=""

newtxt3=""

newtxt4=""

#first way to readline

f = open("duplicate_txt.txt","r+")    # 返回一个文件对象 

line = f.readline()           # 调用文件的 readline()方法

while line: 

  original_list1.append(line)         

  line = f.readline() 

f.close()

#use "set()" remove duplicate str in the list

# in this way,list will sort randomly

newlist1 = list(set(original_list1))

#newlist1 = {}.fromkeys(original_list1).keys() #faster

#rebuild a new txt

newtxt1="".join(newlist1)

f1 = open("noduplicate1.txt","w")

f1.write(newtxt1)

f1.close()

###################################################################

#second way to readline

for line in open("duplicate_txt.txt","r+"): 

  original_list2.append(line)

newlist2 = list(set(original_list2))

newlist2.sort(key=original_list2.index)         #sort

#newlist2 = sorted(set(original_list2),key=l1.index)  #other way

newtxt2="".join(newlist2)

f2 = open("noduplicate2.txt","w")

f2.write(newtxt2)

f2.close()

###################################################################

#third way to readline

f3 = open("duplicate_txt.txt","r") 

original_list3 = f3.readlines()       #读取全部内容 ，并以列表方式返回

for i in original_list3:          #遍历去重

  if not i in newlist3:

      newlist3.append(i)

newtxt3="".join(newlist3)

f4 = open("noduplicate3.txt","w")

f4.write(newtxt3)

f4.close()

###################################################################

#fourth way

f5 = open('duplicate_txt.txt',"r+")

try:

  original_list4 = f5.readlines()

  [newlist4.append(i) for i in original_list4 if not i in newlist4]

  newtxt4="".join(newlist4)

  f6 = open("noduplicate4.txt","w")

  f6.write(newtxt4)

  f6.close()

finally:

  f5.close()

f = open("test.txt"，"w")

f.write(u"你好")

f = open("test.txt"，"w")

text=u"你好"

text=text.encode(encoding='utf-8')

f.write(text)

f = open("test.txt"，"w")

try:

  text=u"你好"

  text=text.encode(encoding='utf-8')

  f.write(text)

except: IOError as e:

  print("oops,%s"%e.args[0])

finally:

  f.close()

with open("test.txt"，"w") as f:

  text=u"你好"

  f.write(text.encode(encoding='utf-8'))

from io import open

with open("test.txt"，"w",encoding='utf-8') as f:

  f.write(u"你好")