🌐 Mailman 3 July 2008 - Python-list - python.org

Please check my understanding...
by Tobiah July 1, 2008

July 1, 2008

list.append([1,2]) will add the two element list as the next element of the list. list.extend([1,2]) is equivalent to list = list + [1, 2] and the result is that each element of the added list becomes it's own new element in the original list. Is that the only difference? >From the manual: s.extend(x) | same as s[len(s):len(s)] = x But: (python 2.5.2) >>> a [1, 2, 3] >>> a[len(a):len(a)] = 4 Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: can only assign an iterable >>> Also, what is the difference between list[x:x] and list[x]? >>> a[3:3] = [4] >>> a [1, 2, 3, 4] ** Posted from http://www.teranews.com **

4 3

ImportError: No module named _md5
by neridaj＠gmail.com July 1, 2008

July 1, 2008

Hello, Does anyone know how to fix this error when trying to build MySQL- python-1.2.2: python setup.py build Traceback (most recent call last): File "setup.py", line 5, in <module> import ez_setup; ez_setup.use_setuptools() File "/Users/jasonnerida/Downloads/MySQL-python-1.2.2/ez_setup.py", line 83, in use_setuptools egg = download_setuptools(version, download_base, to_dir, download_delay) File "/Users/jasonnerida/Downloads/MySQL-python-1.2.2/ez_setup.py", line 111, in download_setuptools import urllib2, shutil File "/opt/local/Library/Frameworks/Python.framework/Versions/2.5/ lib/python2.5/urllib2.py", line 91, in <module> import hashlib File "/opt/local/Library/Frameworks/Python.framework/Versions/2.5/ lib/python2.5/hashlib.py", line 133, in <module> md5 = __get_builtin_constructor('md5') File "/opt/local/Library/Frameworks/Python.framework/Versions/2.5/ lib/python2.5/hashlib.py", line 60, in __get_builtin_constructor import _md5 ImportError: No module named _md5 I then tried installing py25-hashlib via macports, which never completes: sudo port install py25-hashlib Password: Waiting for lock on /opt/local/var/macports/build/ _opt_local_var_macports_sources_rsync.macports.org_release_ports_python_py25- hashlib/work/.macports.py25-hashlib.state Do I need to completely reinstall python? I'm using 2.5.2 which shipped with Leopard. Thanks for any help, Jason

2 1

Convert string to char array
by Brandon July 1, 2008

July 1, 2008

How do I convert a string to a char array? I am doing this so I can edit the string received from an sql query so I can remove unnecessary characters.

3 3

Implementing an 8 bit fixed point register
by nickooooola July 1, 2008

July 1, 2008

Hello to all I'm about to write a simulator for a microcontroller in python (why python? because I love it!!!) but I have a problem. The registry of this processor are all 8 bit long (and 10 bit for some other strange register) and I need to simulate the fixed point behaviour of the register, and to access the single bit. f.x. (this is a pseudo python session, only for understanding) >>> reg1 = fixed_int(8) >>> reg2 = fixed_int(10) >>> reg1[0].set() or >>> reg1[0] = 1 # or True? how to rapresent a binary bit >>> reg1[0] 1 >>> reg1[1] 0 >>> reg1[9] <exception .... blah blah not in range> >>> reg2 = 0x7FE # in binary 11111111110 , or 11 bit long >>> reg2 0x7FE #or 1111111110, the memorization truncate the upper bits ( or perhaps generate an exception?) >>> reg2 += 0x02 #the result is 10000000000, again not contained in 10 bit >>> reg2 0x00 # truncated again >>> myprocessor.flags['z'] 1 # or True? Z flag indicated an overflow in arithmetic operations Is possibile to do so in python? thanks

5 5

connecting to DBMS
by varun chadha July 1, 2008

July 1, 2008

i am a newbie to python and is working on an application which needs to connect to the database. can anyone guide me through the DBMS that i can use and the module to connect to it. currently i have MySQL installed using the link on the python.org site but is unable to connect to it through python. pls specify the link to the tutorials which can guide to connect and execute my query. hopes u understood what i meant to say. thanks in advance

2 1

How to use gnu readline library in program?
by Grant Edwards July 1, 2008

July 1, 2008

I'm trying to figure out how to use the gnu readline library so that when my program is prompting the user for input there is line editing and history support. I've read and re-read the documentation for the "readline" module in the standard library and I still can't figure out how to use the module or even if the module is intended to do what I want. The example code all seems to be about on how to modify the behavior of an interactive Python interpreter session so you have things like auto-completion of Python identifiers. What I want to do is replace sys.stdin.readline() with something that will provide the user with line editing and history recall. In other languages, one uses the Gnu readline library to do that, but my reading of the Python library documentation is that's not what the Python readline module is for. Am I wrong? -- Grant Edwards grante Yow! On the road, ZIPPY at is a pinhead without a visi.com purpose, but never without a POINT.

2 2

Re: ask for a RE pattern to match TABLE in html
by David C. Ullrich July 1, 2008

July 1, 2008

In article <mailman.877.1214489508.1044.python-list(a)python.org>, Cédric Lucantis <omer(a)no-log.org> wrote: > Le Thursday 26 June 2008 15:53:06 oyster, vous avez écrit : > > that is, there is no TABLE tag between a TABLE, for example > > <table >something with out table tag</table> > > what is the RE pattern? thanks > > > > the following is not right > > <table.*?>[^table]*?</table> > > The construct [abc] does not match a whole word but only one char, so > [^table] means "any char which is not t, a, b, l or e". > > Anyway the inside table word won't match your pattern, as there are '<' > and '>' in it, and these chars have to be escaped when used as simple text. > So this should work: > > re.compile(r'<table(|[ ].*)>.*</table>') > ^ this is to avoid matching a tag name starting with > table > (like <table_ext>) Doesn't work - for example it matches '<table></table><table></table>' (and in fact if the html contains any number of tables it's going to match the string starting at the start of the first table and ending at the end of the last one.) -- David C. Ullrich

4 7

dynamically load from module import xxx
by Neal Becker July 1, 2008

July 1, 2008

What is a good way to emulate: from module import xxx where 'module' is a dynamically generated string? __import__ ('modulename', fromlist=['xxx']) seems to be what I want, but then it seems 'xxx' is not placed in globals() (which makes me wonder, what exactly did fromlist do?)

2 3

Embedding Python
by Marcin Krol July 1, 2008

July 1, 2008

Hello everyone, I'm trying to embed Python interpreter in C code, but in a specific way: loading compiled bytecode into a memory location and executing it (don't ask why, complicated reasons). PyImport_ExecCodeModule seems like obvious candidate, docs say: "Given a module name (possibly of the form package.module) and a code object read from a Python bytecode file or obtained from the built-in function compile(), load the module." Code: ---cut--- #include <Python.h> #include <stdio.h> #include <stdlib.h> #include <syslog.h> #include <unistd.h> int load_file(char *fname, unsigned char** result) { int size = 0; FILE *f = fopen(fname, "rb"); if (f == NULL) { *result = NULL; return -1; } fseek(f, 0, SEEK_END); size = ftell(f); *result = (unsigned char *) malloc(size+1); fseek(f, 0, SEEK_SET); size = fread(*result, sizeof(unsigned char), size, f); return size; } int main(int argc, char **argv) { int size; unsigned char *python_code; PyObject *mainobj; size = load_file("multiply.pyc", &python_code); Py_Initialize(); mainobj = PyImport_ExecCodeModule("multiply", (PyObject *) python_code); Py_Finalize(); } ---cut--- Compiling it following way works fine: ${CC} testit.c -g -o testit -I/usr/include/python2.4 -lpython2.4 -lm -lutil -lpthread -ldl -L/usr/lib/python2.4/config However, the damn thing crashes on this call: 33 mainobj = PyImport_ExecCodeModule("multiply", (PyObject *) python_code); (gdb) n Program received signal SIGSEGV, Segmentation fault. 0x0804e7f6 in PyImport_ExecCodeModuleEx () The .pyc file woks just fine in Python interpreter: >>> import multiply >>> multiply.multiply() The result of 12345 x 6789 : 83810205 83810205 >>> What I am doing wrong? Please help.

2 3

Re: Embedding Python
by Carsten Haese July 1, 2008

July 1, 2008

Marcin Krol wrote: > Hello everyone, > > I'm trying to embed Python interpreter in C code, but in a specific way: > loading compiled bytecode into a memory location and executing it (don't > ask why, complicated reasons). > > PyImport_ExecCodeModule seems like obvious candidate, docs say: > > "Given a module name (possibly of the form package.module) and a code > object read from a Python bytecode file or obtained from the built-in > function compile(), load the module." > [...] > mainobj = PyImport_ExecCodeModule("multiply", (PyObject *) > python_code); > [...] python_code is a C string containing the raw bytes from your pyc file. Casting that to a PyObject pointer will not magically transform it into a Python code object. A pyc file contains the following: 1) An 8 byte header containing a magic number. 2) A "marshal" serialization of the code object. So, in order to transform those contents into a code object, you need to skip the 8 byte header and an unmarshal the rest. Basically, replace the line above with something like this: codeobj = PyMarshal_ReadObjectFromString(python_code+8, size-8); mainobj = PyImport_ExecCodeModule("multiply", codeobj); where codeobj is of type (PyObject *). Once that works, add magic number checking and exception handling to taste. Hope this helps, -- Carsten Haese http://informixdb.sourceforge.net

2 1