Python技巧整理之文件读写

大家在使用Python的时候，如果知道一些小技巧，那么工作效率会有很大的提高。小编整理了关于文件读写的Python技巧，都是干货，希望能对大家有一点小小的帮助吧!

# python2 str unicode

# python3 bytes str

# python2

s = u'你好'

s.encode('utf8') #存储到文件中的格式

f = open('hello.txt','w')

f.write(s.encode('utf8'))

f.close()

f = open('hello.txt','r')

t = f.read().decode('utf8') # 你好

f.close()

# python3 字符串就是unicode

strb = b'asdfasdfsdg'

s = '你好'

f = open('hello2.txt','wt',encoding='utf8') # 自动完成编解码

f.write(s)

f.close()

f = open('hello2.txt','rt',encoding='utf8')

s = f.read()

f.close()

# 处理二进制文件 处理音频文件，将音量调小保存

f = open('demo.wav','rb')

info = f.read(44) #文件头

import struct

struct.unpack('h',info[22:24]) #处理文件头 数据运算

struct.unpack('i',infi[24:28])

f.seek(0,2)

f.tell()

n = (f.tell()-44) /2

import array

buf = array.array('h',(0 for _ in xrange(n)))

f.seek(44)

f.readinto(buf)

for i in xrange(n): buf[i] /= 8

f2 = open('demo2.wav','wb')

f2.write(info)

buf.tofile(f2)

f2.close()

# 使用临时文件

# 自动删除，不占内存

from tempfile import TemporaryFile,NamedTemporaryFile

f = TemporaryFile() # 系统文件系统找不到

f.write('abcddee'*100000)

f.seek(0)

f.read(100)

ntf = NamedTemporaryFile(delete=False) # 能找到文件，默认关闭以后会删除文件

fname = nft.name

# 设置文件的缓冲

# I/O 操作以块为单位，如4096字节一个块

f = open('test.txt','w'， buffering=2048) # 全缓冲，要写满缓冲才会写到文件中

f = open('test.txt','w'， buffering=1) # 行缓冲，n就会写文件

f = open('test.txt','w'， buffering=1) # 无缓冲，实时写

f.write('abc')

# 将文件映射到内存

import mmap

f = open('demo.bn','r+b')

f.fileno()

m = mmap.mmap(f.fileno(),0,access=mmpa.ACCESS_WRITE,offset=mmap.PAGESIZE)

# 得到字节数组

m[4:8] = 'xff'*4 # 修改直接改变文件内容

# 读写csv数据

from urllib import urlretrieve

urlretrieve('http://table.finance.yahoo.com/table.csv?s=000001.sz','pingan.csv')

rf = open('pingan.csv','rb')

import csv

reader = csv.reader(rf)

header = reader.next()

wf = open('pingan_c.csv','wb')

writer = csv.writeer(wf)

writer.writerow(header)

rf.close()

wf.close()

# 读写json数据

import requests

import json

from record import Record

record = Record(channel=1)

audioData = record.record(2)

from secret import API_KEY,SECRET_KEY

authUrl = "https://openapi.baidu.com/oauth/2.0/token?grant_type=client_credentials&client_id=" + API_KEY + "&client_secret=" +

SECRET_KEY

response = requests.get(authUrl)

res = json.loads(response.content)

token = res['access_token']

#百度语音识别

cuid = 'xxxxxxxxxxxxx'

srvUrl = 'http://vop.baidu.com/server_api?cuid=' + cuid + '&token=' + token

heepHeader = {'Content-Type': 'audio/wav; rate = 8000'}

response = requests.post(srvUrl,headers=httpHeader,data=audioData)

res = json.loads(response.content)

text = res['result'][0]

print text

# json.dumps() python对象(列表、字典等)转换成json字符串

# json.dumps(data,sort_keys=True)

# json.loads() json字符串转换成python对象

with open('demo.json','wb') as f:

json.dump(l,f) # 将l数据写到文件

# 构建xml文档

from xml.etree.ElementTree import parse

with open('demo.xml') with f:

et = parse(f)

root = et.getroot()

root.tag

root.attrib

root.text

#root.getchildren()

for child in root:

print child.get('name')

root.find('country')

root.findall('country') # 直接子元素

for e in root.iterfind('country'):

print e.get('name')

from xml.etree.ElementTree import Element,ElementTree,tostring

e = Element('Data')

e.set('name','abc')

e2 = Element('Row')

e3 = Element('Open')

e3.text = '8.80'

e2.append(e3)

e.append(e2)

tostring(e)

et = ElementTree(e)

et.write('demo.xml')

# 读写excel文件

import xlrd,xlwt

book = xlrd.open_workbook('demo.xls')

book.sheets()

sheet = book.sheet_by_index(0)

rows = sheet.nrows

cols = sheet.ncols

cell = sheet.cell(0,0) #(0,0)单元格

cell.ctype

cell.value

row = sheet.row(1) #cell对象列表

data = sheet.row_values(1,1) #第1列跳过第一格的值列表

sheet.put_cell(0,cols,xlrd.XL_CELL_TEXT,u'Total',None)

wbook = xlwt.Workbook()

wsheet = wbook.add_sheet('sheet1')

style = xlwt.easyxf('align: vertical center,horizontal center')

wsheet.write(rows,cols,sheet.cell_value(rows,cols),style)

wsheet.save('output.xls')

以上就是文件读写Python技巧的整理，觉得本篇文章有用的同学不妨分享出去，让更多人看见。