cannot read ascii character 26?

Question

I wrote a stream in a file in text mode.

# python code
f = open(\"somewhere in my computer\",\"w\")
f.write(\"Hello\\nWorld\")
f.write(chr(26)) # writing asc         


        

Answer 1

This code words for me to open and read the file on Windows. Furthermore, using curses, you can get a "^" representation of any control characters that may be in your file.

import curses.ascii

filename = "myfile.txt"
f = open(filename,"w")
f.write("Hello\nWorld")
f.write(chr(26)) # writing ascii character #26 to file 
f.write("hhh")
f.close()

with open(filename,'r') as f:
    for line in f:
        line2 = [ curses.ascii.unctrl(c) if curses.ascii.iscntrl(c) else c for c in line]
        print("".join(line2))

Gives output:
Hello^J
World^Zhhh

Answer 2

The problem is because of the windows. 0x1A is Ctrl-Z, and DOS used that as an end-of-file marker. Python uses the Windows CRT function _wfopen, which implements the "Ctrl-Z is EOF" semantics. If your file wasn't an exact multiple of 128 bytes, you needed a way to mark the end of the text. This article implies that the selection of Ctrl-Z was based on an even older convention used by DEC.