How to read and write Files with Python

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# python2 str unicode

# python3 bytes str

# python2

S = u 'Hello'

S.encode ('utf8') # format stored in the file

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

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

F.close ()

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

T = f.read (). Decode ('utf8') # Hello

F.close ()

# python3 string is unicode

Strb = biconasdfasdfsdg'

S = 'Hello'

F = open ('hello2.txt',' wt', encoding='utf8') # automatically complete codec

F.write (s)

F.close ()

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

S = f.read ()

F.close ()

# deal with binaries, process audio files, turn the volume down and save

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

Info = f.read (44) # header

Import struct

Struct.unpack ('hobblemain info [22:24]) # handles file header data operations

Struct.unpack ('iPrependium infi [24:28])

F.seek (0Pol 2)

F.tell ()

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

Import array

Buf = array.array ('hags, (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 ()

# use temporary files

# automatically delete and do not occupy memory

From tempfile import TemporaryFile, NamedTemporaryFile

F = TemporaryFile () # system file system not found

F.write ('abcddee'*100000)

F.seek (0)

F.read (100)

Ntf = NamedTemporaryFile (delete=False) # the file can be found. The file will be deleted after it is turned off by default.

Fname = nft.name

# set file buffering

# I move O operations in blocks, such as 4096 bytes per block

F = open ('test.txt',' walled, buffering=2048) # fully buffered, which will not be written to the file until it is fully buffered

F = open ('test.txt',' wicked, buffering=1) # line buffer,\ nThe file will be written

F = open ('test.txt',' walled, buffering=1) # No buffer, real-time write

F.write ('abc')

# Mapping files to memory

Import mmap

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

F.fileno ()

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

# get a byte array

M [4:8] ='\ xff'*4 # modify the file content directly

# read and write csv data

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 ()

# read and write json data

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']

# Baidu speech recognition

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 objects (lists, dictionaries, etc.) are converted to json strings

# json.dumps (data, sort_keys=True)

# json.loads () json string converted to python object

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

Json.dump (l, f) # writes l data to a file

# Building xml documents

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') # direct child element

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')

# read and write excel files

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 (0B0) # (0B0) cell

Cell.ctype

Cell.value

Row = sheet.row (1) # cell object list

Data = sheet.row_values (1,1) # column 1 skips the list of values in the first box

Sheet.put_cell (0, cols, xlrd.XL_CELL_TEXT, upright Totalions, 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')

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