[Tutor] checking if data files are good, readable, and exist
I would like to check to see if the data files are good, readable, and exist. I have checked to see if they exist, but their is a possibility that the data file might be binary, and I would like to have a sys.exit for that as well. if not os.path.isfile(A_data) or not os.path.isfile(B_data)\ or not os.path.isfile(C_data) or not os.path.isfile(D_data): sys.exit(14) -- The game of science can accurately be described as a never-ending insult to human intelligence. - João Magueijo ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] checking if data files are good, readable, and exist
Bryan Fodness wrote: I would like to check to see if the data files are good, readable, and exist. I have checked to see if they exist, but their is a possibility that the data file might be binary, and I would like to have a sys.exit for that as well. You're going to be asked a lot of questions along the lines of What do you mean by binary?. I'm going to assume you mean: has things other than ordinary letters, numbers and punctuation in it. In today's internationalised and Unicoded world that's a highly dodgy assumption, but I'm going to go with it. To compound the crudeness of my approach, I'm going to assume that anything 126 is binary (thus dodging the more complicated issue of the 0-31 control chars). code def is_binary (filename): return any (ord (c) 126 for c in open (filename).read ()) print is_binary (file1.txt) /code Obviously, if you know any of the files is going to be massive, you'll want to do something a bit smarter than this. TJG ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] %(value1, value2) what does this returns
Hi List, def __request(symbol, stat): url = 'http://finance.yahoo.com/d/quotes.csv?s=%sf=%s' % (symbol, stat) return urllib.urlopen(url) I want to know in this % (symbol, stat) returns thanks for help Regards, Vishwajeet ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] %(value1, value2) what does this returns
Vishwajeet wrote... I want to know in this % (symbol, stat) returns In itself it returns nothing. The '%' is used as the 'string interpolation operator' here. http://docs.python.org/lib/typesseq-strings.html print %d kilos of %s for %f euro % (2,mangos,3.75) 2 kilos of mangos for 3.75 euro Greetings, -- The ability of the OSS process to collect and harness the collective IQ of thousands of individuals across the Internet is simply amazing. - Vinod Vallopillil http://www.catb.org/~esr/halloween/halloween4.html ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] %(value1, value2) what does this returns
thanks to all of you for your responses; On Wed, Jul 23, 2008 at 12:18 AM, Michiel Overtoom [EMAIL PROTECTED] wrote: Vishwajeet wrote... I want to know in this % (symbol, stat) returns In itself it returns nothing. The '%' is used as the 'string interpolation operator' here. http://docs.python.org/lib/typesseq-strings.html print %d kilos of %s for %f euro % (2,mangos,3.75) 2 kilos of mangos for 3.75 euro Greetings, -- The ability of the OSS process to collect and harness the collective IQ of thousands of individuals across the Internet is simply amazing. - Vinod Vallopillil http://www.catb.org/~esr/halloween/halloween4.htmlhttp://www.catb.org/%7Eesr/halloween/halloween4.html ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] %(value1, value2) what does this returns
vishwajeet singh wrote: Hi List, def __request(symbol, stat): url = 'http://finance.yahoo.com/d/quotes.csv?s=%sf=%s http://finance.yahoo.com/d/quotes.csv?s=%sf=%s' % (symbol, stat) return urllib.urlopen(url) I want to know in this % (symbol, stat) returns Assume symbol = foo and stat = bar. Then url = 'http://finance.yahoo.com/d/quotes.csv?s=foof=bar http://finance.yahoo.com/d/quotes.csv?s=%sf=%s -- Bob Gailer 919-636-4239 Chapel Hill, NC ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] checking if data files are good, readable, and exist
W W [EMAIL PROTECTED] wrote Am I wrong in thinking that /all/ files are stored as binary? No, thats quite right. python opens them, it automagically opens them in a more readable format, But that isn't. Python just reads the data and interprets it as text if you specify a text file - the default - or as raw data if you use rb. Python doesn't alter the data in any way it simply assumes that its text and interprets the bytes according to the current alphabet. Thus it reads the value 65 and interprets it as 'A' (assuming ASCII) in text mode or just as the bit pattern 0101 in binary. The application must then interpret the bits in whatever way it considers appropriate - ass an integer, a bitmask, part of a graphic image etc. The important point is that there is no distinction between binary data or text data in the file itself its just how it is interpreted that distinguishes them. (This is not completely true on some OS where text files always have an EOF marker, but it is itself just a binary value!) None of which helps the OP other than to highlight the difficulty of determining if a file in binary or not. We can sometimes tell if a file is not text - if it uses ASCII - by looking at the range of byte values, but thats sloowww... but we can never be sure that a file is non text. (We can also check for common file headers such as postscript, GIF, MP3, JPEG, MIDI, etc etc but even they can be misleading if they just coincidentally look valid) HTH, Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] checking if data files are good, readable, and exist
Alan Gauld wrote:
But that isn't. Python just reads the data and interprets it
as text if you specify a text file - the default - or as raw data
if you use rb.
But it DOES handle line-ends in an OS independent manner. Windows uses
CR-LF as a line end, whereas Unix, Linux, Mac use (just CR or is it LF?).
Python presents line-ends uniformly as \n when you open the file in text
mode.
Witness: (on Windows)
f = open('c:/foo.txt', 'r')
f.read()
'this line contains as\nbut this has as\n'
f = open('c:/foo.txt', 'rb')
f.read()
'this line contains as\r\nbut this has as\r\n'
[snip]
--
Bob Gailer
919-636-4239 Chapel Hill, NC
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[Tutor] OT looking for help creating a thumbnail
Hi, I'm sorry this is OT but you guys are very knowledgeable with the world of python. I already tried the python list. - no response. I need a py tool that will provide a thumbnail (bmp?) from a video (avi, wmv) that will be cross platform (linux, windows). Research has provided pymedia for Linux but I haven't found anything for windows. Hopefully, someone has had to do this in the past and knows what has to be done. Thanks in Advance, Johnf ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] checking if data files are good, readable, and exist
bob gailer [EMAIL PROTECTED] wrote But that isn't. Python just reads the data and interprets it as text if you specify a text file - the default - or as raw data if you use rb. But it DOES handle line-ends in an OS independent manner. OK, I'll grant you that small piece of data manipulation. :-) (Although it could be argued that even that is just translating two bytes into one character in the set.) Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] question about socket status
On Mon, Jul 21, 2008 at 1:25 PM, Rupp, Romaine [EMAIL PROTECTED] wrote: Hello, I am new to programming with python and sockets. I would like to determine the status of a socket as it is returned when you do 'netstat –a | grep port#'. I would like to know if the socket state is ESTABLISHED, LISTEN , CLOSE_WAIT, etc. Is there a way to get this information through a socket call? I've tried using socket.getperrname() function, but that only tells if there is a connection. Is there a way to get more information on the state of the socket connection? If you're on linux, you could try poking around /proc/net. See, for example: http://www.linuxdevcenter.com/pub/a/linux/2000/11/16/LinuxAdmin.html But I think invoking netstat and parsing the output from python might work well enough. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Online class/education for Python?
http://mail.python.org/mailman/listinfo/tutor Hi, I have the Second Edition of PPftAB, and it was published in 2006. The version of Python used in PPftAB2E is Python 2.3.5. I'm running Python 2.4.4 on Debian GNU/Linux. So far, no problems. The only problems I can see you having is if the examples in your book use a feature that is no longer used in Python. Otherwise, I don't think you'll have any problems. The core principles of Python Programming remain the same. Just out of curiosity, when was the First Edition published? Which version of Python is used in the book? It was done in 2003. The version of python the book uses is 2.2.3. However, it does talk about using the latest versions of python. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
