Pathological regular expression
Hi all, I'm having a weird problem with a regular expression (tested in 2.6 and 3.0): Basically, any of these: _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$') _re_comments = re.compile(r'^(([^#]+|\\.|"([^"\\]+|\\.)*")*)#.*$') _re_comments = re.compile(r'^(([^"]+|\\.|"([^"\\]+|\\.)*")*)#.*$') followed by for example, line = r'~/.[m]ozilla/firefox/*.default/chrome' print(_re_comments.sub(r'\1', line)) ...hangs the interpreter. For reference, if the first command had been _re_comments = re.compile(r'^(([^z]+|\\.|"([^"\\]+|\\.)*")*)#.*$') (off by one character z) it works fine, and all the equivalent operations work in sed and awk. Am I missing something about Python RE's? -David -- http://mail.python.org/mailman/listinfo/python-list
Re: Pathological regular expression
On Apr 9, 2:56 am, David Liang wrote: > Hi all, > I'm having a weird problem with a regular expression (tested in 2.6 > and 3.0): > > Basically, any of these: > _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > _re_comments = re.compile(r'^(([^#]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > _re_comments = re.compile(r'^(([^"]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > > followed by for example, > line = r'~/.[m]ozilla/firefox/*.default/chrome' > print(_re_comments.sub(r'\1', line)) > > ...hangs the interpreter. For reference, if the first command had been > _re_comments = re.compile(r'^(([^z]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > > (off by one character z) it works fine, and all the equivalent > operations work in sed and awk. Am I missing something about Python > RE's? > > -David The problem was the redundant +'s; the fixed RE is _re_comments = re.compile(r'^(([^#"\\]|\\.|"([^"\\]|\\.)*")*)#.*') -- http://mail.python.org/mailman/listinfo/python-list
Re: Pathological regular expression
On Apr 9, 2:56 am, David Liang wrote: > Hi all, > I'm having a weird problem with a regular expression (tested in 2.6 > and 3.0): > > Basically, any of these: > _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > _re_comments = re.compile(r'^(([^#]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > _re_comments = re.compile(r'^(([^"]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > > followed by for example, > line = r'~/.[m]ozilla/firefox/*.default/chrome' > print(_re_comments.sub(r'\1', line)) > > ...hangs the interpreter. For reference, if the first command had been > _re_comments = re.compile(r'^(([^z]+|\\.|"([^"\\]+|\\.)*")*)#.*$') > > (off by one character z) it works fine, and all the equivalent > operations work in sed and awk. Am I missing something about Python > RE's? > > -David The problem was the redundant +'s; the fixed RE is _re_comments = re.compile(r'^(([^#"\\]|\\.|"([^"\\]|\\.)*")*)#.*') -- http://mail.python.org/mailman/listinfo/python-list
Running an interactive subprocess with Popen
Hello, Sorry for the newbie question. How do I run a program that could block, waiting for user input, using subprocess.Popen? For example, from subprocess import * def foo(): a = Popen(['python'] ...) I want to be able to get input from the user and send input to the subprocess, printing stdout and stderr as data becomes available, then return once the subprocess exits. Is it possible to send to the subprocess keyboard interrupts, EOF, and such? I tried doing stdout=PIPE, stderr=PIPE, stdin=PIPE. I tried using communicate(), but could only call it once; subsequent calls raised "ValueError: I/O operation on closed file." And both a.stdout.read() and a.stderr.read() blocked the program. Any help would be much appreciated. -David -- http://mail.python.org/mailman/listinfo/python-list
