How to open a file to read and write

Opening Files

You can open files with the open function, which has the following syntax:

open(name[, mode[, buffering]])

The open function takes a file name as its only mandatory argument, and returns a file object. The mode and buffering arguments are optional.

The following code opens a file called somefile.txt stored in the directory C:\text,

f = open(r'C:\text\somefile.txt')

If the file doesn't exist, you may see an exception traceback. If you use open with only a file name, the file is opened in read from.

If you want to write to the file, you have to state that explicitly, supplying a mode. The mode argument are summarized in the following table.

'r' Read mode
'w' Write mode
'a' Append mode
'b' Binary mode (added to other mode)
'+' Read/write mode (added to other mode)

The write mode enables you to write to the file.

The '+' can be added to any of the other modes to indicate that both reading and writing is allowed. So 'r+' can be used when opening a text file for reading and writing.

The 'b' mode changes the way the file is handled. rb' to read a binary file.

turn file content to list or tuple

print list(open(''))
print tuple(open(''))
print '&&'.join(open(''))
#   www  .j  a va 2  s  . c o m
a, b, c, d = open('')

print a
print b
print c
print d

Working with File Objects

open returns a file object, which has methods and attributes for getting information about and manipulating the opened file.

f = open("aFile.txt", "rb")        
# from  ww w  .j av a  2  s . c  o m
print f                                            

print f.mode                                       


Use file pointer to get file content

f = open('somefile.txt', 'w')
print >> f, 'This is the first line'
print >> f, 'This is the second line'
print >> f, 'This is the third line'
f.close()# from   w  ww.  ja va2 s  . c  o  m

Home »
  Python »
    Advanced Features »

Exception Handling