Windows vs. file.read

[Mike]

I have a ppm file that python 2.5 on Windows XP cannot read
completely.
Python on linux can read the file with no problem
Python on Windows can read similar files.
I've placed test code and data here:
http://www.cs.ndsu.nodak.edu/~hennebry/ppm_test.zip
Within the directory ppm_test, type
python ppm_test.py
The chunk size commentary occurs only if file.read cannot read enough
bytes.
The commentary only occurs for the last file.
Any ideas?
Any ideas that don't require getting rid of Windows?
It's not my option.

 

[MRAB]

I have a ppm file that python 2.5 on Windows XP cannot read
completely.
Python on linux can read the file with no problem
Python on Windows can read similar files.
I've placed test code and data here:
http://www.cs.ndsu.nodak.edu/~hennebry/ppm_test.zip
Within the directory ppm_test, type
python ppm_test.py
The chunk size commentary occurs only if file.read cannot read enough
bytes.
The commentary only occurs for the last file.
Any ideas?
Any ideas that don't require getting rid of Windows?
It's not my option.

You should open the files in binary mode, not text mode, ie file(path,
"rb"). Text mode is the default. Not a problem on *nix because the line
ending is newline.

 

[David Robinow]

I have a ppm file that python 2.5 on Windows XP cannot read
completely.
Python on linux can read the file with no problem
Python on Windows can read similar files.
I've placed test code and data here:
http://www.cs.ndsu.nodak.edu/~hennebry/ppm_test.zip
Within the directory ppm_test, type
python ppm_test.py
The chunk size commentary occurs only if file.read cannot read enough
bytes.
The commentary only occurs for the last file.
Any ideas?
Any ideas that don't require getting rid of Windows?
It's not my option.

Open the files in binary mode. i.e.,
x=Ppm(file("ff48x32.ppm",'rb'))
x=Ppm(file("bw48x32.ppm",'rb'))
x=Ppm(file("bisonfootball.ppm",'rb'))

You were just lucky on the first two files.

 

[Mike]

You should open the files in binary mode, not text mode, ie file(path,
"rb"). Text mode is the default. Not a problem on *nix because the line
ending is newline.

Thanks.
That was it.

 

[Lawrence D'Oliveiro]

You should open the files in binary mode, not text mode, ie file(path,
"rb"). Text mode is the default. Not a problem on *nix because the line
ending is newline.

We used to pride ourselves on not having to worry about text versus binary
I/O modes on *nix, but I’m beginning to think the reality is we have to
adopt it.

To start with, it means we can automatically handle different newline
conventions with text files originating on different systems.

 

[MRAB]

We used to pride ourselves on not having to worry about text versus binary
I/O modes on *nix, but I’m beginning to think the reality is we have to
adopt it.

To start with, it means we can automatically handle different newline
conventions with text files originating on different systems.

In Python 3 the difference is important because binary mode works with
bytes and text mode works with strings, plus the file encoding and line
endings.

 

[Lawrence D'Oliveiro]

In Python 3 the difference is important because binary mode works with
bytes and text mode works with strings, plus the file encoding and line
endings.

Yeah, that seems like a reasonable approach—make you decide up-front what
exactly is the sort of file content you’re dealing with.