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Aug 16th, 2005

reading from a file with python

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I want to read everything from a file using python. the one problem i am having (note: EVERYTHING from a file) is that python is returning an EOFError when i know that it's not the end of the file, is there any way to just read the damn thing till the computer crashes or at least untill the file i want to read from has been literaly sucked dry.

basically is it possible to either skip an eof key and keep reading or specify my own.

thanks
alex

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a1eio

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Junior Poster

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Aug 16th, 2005

Re: reading from a file with python

a1eio,

What method are you using to read the file? Are you doing something like this?

Python Syntax (Toggle Plain Text)
f = open(filename, "r")
text = f.read()
print text
f = open(filename, "r")
text = f.read()
print text

Is the file very large?

G-Do

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Junior Poster

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Aug 16th, 2005

Re: reading from a file with python

yes
when i do text = f.read()
then when i print text i get a little bit then if i do it again i get a load more then if i try again i don't get anything and i am positive that there is still much much more

Python Syntax (Toggle Plain Text)
>>> f = file("file.txt","r")
>>> f.read()
'\x17\xa9\xaa\t\xb5\x11%$\xe9e\xcf\xaf\x1e\xee\xcf\xcb\xab\xef\xd7_r\x95\x94^ \xa8\x9e\x9b\xe4+\xcen\x9fY^\xeaI\x13\xbc\x08\xb4G\x7fiHP['
>>> f.read()
'\xa8\xca\xc9)\xde\xfa7|9l\xdc%\xe6\x17\xc5\x96F6\xc8Jx&\xf4\x0b\xb2&\x87\xbe\xe5\xeb>\x0f\xf6\xa7t\xa5"m\xfeM\xbd\x9f\x18\xbd\xf5MVT\xb2 \x13\x94S\xd0\x1c\x9b\\\xb9.g\xcb\x80\x05.-l\x87\x92&e\xd9\xf3\x9c4\xdb\xb0\x13\xee\xd8\x98vA\xf6U\xfdp/\x199\xc3A^\nC\x97\xe7\x9d`i\xf3\x1f\x89\x19\xb8:<2\x1f$\x8b\xe1\xe5K\xb4c\x03S\xbcB\x81\x92\xa9\xd0\xb4\xaaW\xcd\xf3ds\x8c\xb5\x87\xa5\x97L\xc3r0\rX\xd9\x8d(\xac=L\xfdp\x95\xf38yw\xf3e\xff\x07\x08pc=j\xac%\xad\xb7\xc9-6\xefi%\xb7\x7f\xb0\xe3H\xaf\x8f\xbf\x04k\x0b\xc5\xe4\xc9R\xa2\xc4.\xe3F\xfd\x84\x94\x01\xbeb\xaf5\x93\x95\tG+\xe5;\xfe\xe7\x92\xe6\xee8W0\x19NyEu*\xb1>\x7f\x9bc\x11q\x1d\x0c\xe9^:K\xab\xc5dt\xeb\xd4\xd7\x02\x1c\xf6\x8c\xecB\xdb\xb83\xef\xa2\xfb\x89\xd6J\xa6\x98\xaf\x126\xad\xc6\xf6\x84F\xf5\xed\xb8fL\x04|\x130\x18\x7f\xeaH?\xd2-\xed\x9b#6l\xa7W\xbd\xe1\xc4\x9d\xc8\x01\x13s\xbfwU\xa6\x80P\xf3\xdf\xe4\t\xd7\xb9\x96\xae<\xf1\xa6\xbf\x19\xb2\xc0&d\x8bt\x06\xb6\x10i\xb8\x90\xb1\xfb\xa4\xd9\xd5\x0fR\xd2\xb7\x9ax\t\r\xc0K\x92\x13\xe7\xcf\x1e\xe4\xb9\x91\x12\xcbe_\\r"w\x13\x8fF\xdc\xa1\x14\xe6\x16\x96]b7\xc1q\xbdY\xcb\xdb@q\xf3\x1d8\xa8\rHB'
>>> f.read()
' '
>>>
>>> f = file("file.txt","r")
>>> f.read()
'\x17\xa9\xaa\t\xb5\x11%$\xe9e\xcf\xaf\x1e\xee\xcf\xcb\xab\xef\xd7_r\x95\x94^ \xa8\x9e\x9b\xe4+\xcen\x9fY^\xeaI\x13\xbc\x08\xb4G\x7fiHP['
>>> f.read()
'\xa8\xca\xc9)\xde\xfa7|9l\xdc%\xe6\x17\xc5\x96F6\xc8Jx&\xf4\x0b\xb2&\x87\xbe\xe5\xeb>\x0f\xf6\xa7t\xa5"m\xfeM\xbd\x9f\x18\xbd\xf5MVT\xb2 \x13\x94S\xd0\x1c\x9b\\\xb9.g\xcb\x80\x05.-l\x87\x92&e\xd9\xf3\x9c4\xdb\xb0\x13\xee\xd8\x98vA\xf6U\xfdp/\x199\xc3A^\nC\x97\xe7\x9d`i\xf3\x1f\x89\x19\xb8:<2\x1f$\x8b\xe1\xe5K\xb4c\x03S\xbcB\x81\x92\xa9\xd0\xb4\xaaW\xcd\xf3ds\x8c\xb5\x87\xa5\x97L\xc3r0\rX\xd9\x8d(\xac=L\xfdp\x95\xf38yw\xf3e\xff\x07\x08pc=j\xac%\xad\xb7\xc9-6\xefi%\xb7\x7f\xb0\xe3H\xaf\x8f\xbf\x04k\x0b\xc5\xe4\xc9R\xa2\xc4.\xe3F\xfd\x84\x94\x01\xbeb\xaf5\x93\x95\tG+\xe5;\xfe\xe7\x92\xe6\xee8W0\x19NyEu*\xb1>\x7f\x9bc\x11q\x1d\x0c\xe9^:K\xab\xc5dt\xeb\xd4\xd7\x02\x1c\xf6\x8c\xecB\xdb\xb83\xef\xa2\xfb\x89\xd6J\xa6\x98\xaf\x126\xad\xc6\xf6\x84F\xf5\xed\xb8fL\x04|\x130\x18\x7f\xeaH?\xd2-\xed\x9b#6l\xa7W\xbd\xe1\xc4\x9d\xc8\x01\x13s\xbfwU\xa6\x80P\xf3\xdf\xe4\t\xd7\xb9\x96\xae<\xf1\xa6\xbf\x19\xb2\xc0&d\x8bt\x06\xb6\x10i\xb8\x90\xb1\xfb\xa4\xd9\xd5\x0fR\xd2\xb7\x9ax\t\r\xc0K\x92\x13\xe7\xcf\x1e\xe4\xb9\x91\x12\xcbe_\\r"w\x13\x8fF\xdc\xa1\x14\xe6\x16\x96]b7\xc1q\xbdY\xcb\xdb@q\xf3\x1d8\xa8\rHB'
>>> f.read()
' '
>>>

as you can see it does it once then it does it again
so i need some kind of method to keep doing it over and over again untill the whole file has been sucked dry

a1eio

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Junior Poster

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Aug 17th, 2005

Re: reading from a file with python

Can you display that file on an editor? Are you sure you don't have a binary file? In that case use 'rb'

Using the python shell makes things look messy.

bumsfeld

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Nearly a Posting Virtuoso

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Aug 18th, 2005

Re: reading from a file with python

yes on two counts:
1. it looks awfuly messy

2. it was a binary file and it's sorted now

a1eio

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Junior Poster

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Aug 18th, 2005

Re: reading from a file with python

Actually using the Python Shell in this case gave the clue that this was not a text file, since most of the ASCII text characters are less than hex A0.

vegaseat

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DaniWeb's Hypocrite

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Aug 23rd, 2005

Re: reading from a file with python

try f.readlines() instead of f.read()

f.read() is basically doing it's job, reading one line at a time. With readlines() though, the whole thing becomes an object that you can then iterate through or search etc.

i think the online python manual also has some example differences.

hope that helps
sf2k

sf2k

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Newbie Poster

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Aug 23rd, 2005

Re: reading from a file with python

Quote originally posted by sf2k ...

try f.readlines() instead of f.read()

f.read() is basically doing it's job, reading one line at a time. With readlines() though, the whole thing becomes an object that you can then iterate through or search etc.

i think the online python manual also has some example differences.

hope that helps
sf2k

Some basics:
read() reads to EOF, or if opened as a binary, to the last byte
read(n) reads n bytes
readline() reads a line at a time, the line ends with '\n' or EOF.
readlines() uses readline() to read all the lines in a file and returns a list of lines.

The first three functions return a string object, the last function returns a list object. EOF is a special character used as End Of File marker.

vegaseat

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DaniWeb's Hypocrite

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