Contents
- Python / UNO Notes
- Building Python 3000 on Mac OS X (Leopard)
- Date and Time parsing
- Configuring mod_python with Apache2
- Python and memcached
- Sending email using smtplib and Gmail
- This is just cool:
import pydoc pydoc.gui()
To run a command and capture its output
import commands
print commands.getoutput('hostname')
Easy Python Here Documents
Here is some sample code:
#!/usr/bin/env python # encoding: utf-8 name="The President" address=1600 street="Pennsylvania Avenue" print """\ %(name)s lives at %(address)05d %(street)s""" % locals()
Here is the output:
The President lives at 01600 Pennsylvania Avenue
Building a Simple extension on Mac OS X
Here is the source code hello.c:
#include <Python.h>
#include <string.h>
static PyObject *
message(PyObject *self, PyObject *args )
{
char * fromPython, result[64];
if (!PyArg_Parse(args, "(s)", &fromPython))
return NULL;
else {
strcpy( result, "Hello, ");
strcat( result, fromPython );
return Py_BuildValue("s", result);
}
}
static struct PyMethodDef hello_methods[] = {
{"message", message, 1},
{NULL,NULL}
};
void inithello()
{
(void)Py_InitModule("hello", hello_methods);
}
Here is the Makefile. Note that you may have to change the PYINC path to match your Python installation
PYINC = "/Library/Frameworks/Python.framework/Versions/Current/include/python2.5" CC = cc LD = cc CFLAGS = -O -fno-common all: hello.so hello.o: hello.c $(CC) $(CFLAGS) -I$(PYINC) -c hello.c hello.so: hello.o $(LD) -dynamiclib -framework Python -o hello.so hello.o clean: rm hello.o hello.so
Build your extension:
make
Test the result:
python
>>> import python
>>> python.message("bob")
'Hello, bob'
Building and Installing a C Python extension using distutils on Mac OS X
OK, start with the same hello.c file as before. Create a file in the same directory called setup.py as follows:
from distutils.core import setup, Extension
module1 = Extension('hello',
sources = ['hello.c'])
setup (name = 'Hello',
version = '1.0',
description = 'This is a demo package',
ext_modules=[module1]
)
Build your extension as follows:
python setup.py build
Install your module as follows:
sudo python setup.py install
Really cool! See here for more info.
Partial functions in Python
This is a really handy feature. Here is a snippet of code that came from the comp.lang.python newsgroup. It was posted by Christopher King on 2004-06-25:
def partial(func,*args,**kw):
return lambda *a,**k: func(*(args+a),**dict(kw.items()+k.items()))
Here is a trivial example of its use:
def f(x,y):
print "F: x=%d, y=%d, x+y=%d" % (x,y,x+y)
p1 = partial(f,1)
p2 = partial(f,10)
p1(1)
p2(1)
Here is the output of this:
F: x=1, y=1, x+y=2 F: x=10, y=1, x+y=11
If you are running Python 2.5 then this functionality is already built-in. A module called functools defines a partial class that does the same thing (and probably more). Here is a Python 2.5 example:
from functools import partial
def f(x,y):
print "F: x=%d, y=%d, x+y=%d" % (x,y,x+y)
p1 = partial(f,1)
p2 = partial(f,10)
p1(1)
p2(1)
The output is the same.
The nifty Python csv module
Here are two small sample input files:
1.csv
a,b,c d,"e&f",g
2.csv
a b c d e&f g
1.csv is comma/quote delimited and 2.csv is TAB-delimited.
Here is a small program test_csv.py
import csv
print 'first example -- we specify the delimiter and quoting'
files = {'1.csv' : {},
'2.csv' : {
'delimiter' : "\t",
'quoting' : csv.QUOTE_NONE
}
}
for f,o in files.iteritems():
print "reading file %s" % f
reader = csv.reader(open(f, "rb"), **o)
for row in reader:
print row
print 'second example -- we sniff the file first'
sniffer = csv.Sniffer()
for f in files:
print "sniffing file %s" % f
fl = open(f,"rb")
d = sniffer.sniff(fl.readline())
fl.seek(0)
reader = csv.reader(fl, d)
for row in reader:
print row
Here is the output from the program:
$ python test_csv.py first example -- we specify the delimiter and quoting reading file 2.csv ['a', 'b', 'c'] ['d', 'e&f', 'g'] reading file 1.csv ['a', 'b', 'c'] ['d', 'e&f', 'g'] second example -- we sniff the file first sniffing file 2.csv ['a', 'b', 'c'] ['d', 'e&f', 'g'] sniffing file 1.csv ['a', 'b', 'c'] ['d', 'e&f', 'g']