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Python is an interpreted, interactive, object-oriented programming language.
For comparisons with other languages, see
here.
One of the strenghts of Python is that
program development using Python is said to be 5-10 times faster
than with C/C++ and 3-5 times faster than using
Java. < /br>< /br>
A nice mathematical library is SciPy.
It gives a decent computer algebra system within python:
from scipy.stats import *
norm.rvs(scale=2.3)
from scipy import *
p=poly1d([1,2,5])
print p*p*p
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A = mat('[1 2 3; 4 5 7; 4 1 2]')
b = mat('[1;2;6]')
linalg.inv(A)
linalg.solve(A,b)
A = random.rand(5,5)
print linalg.eigvals(A)
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A comprehensive Python-based system for mathematics is
SAGE by William Stein.
Unlike in Perl you
can use it interactively: start by typing "python" and use
it as a calculator.
Entering at the python prompt:
11234123412314L*1234123412341234L
pow(234L,23)
for example multiplies two integers (L is needed after the integer
for long integers) and finds then 23423.
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(1.5+9.5j)*(2.3+9.4j)
returns the product of the two complex numbers, or
abs(2.23423+9.4j)
the absolute value of a complex number.
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Most important mathematical
functions are predefined. You might to load the math module before
using them:
import math
math.sin(0.234234)
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There are many libraries available. For example, to
access random numbers, you use
import random
random.random()
An other library is the calendar:
import calendar
calendar.prcal(2001)
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How to work with lists and dictionaries
can be seen in invert.py.
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How to
define functions in fibonnacci.py
or ulam.py.
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If a file like pi.py is made executable,
then it can be called directly The program
determines pi=3.14159.... to arbitrary many digits. You could
also execute the program by directing in into python. You can also start
up python, then type "import pi.py" at the python prompt.
When looking at pi.py , you see the lack
of parentheses. This is achieved by text structure. Unlike in
other languages, it matters how the indentations are put.
To see an other example, look at factorize.py,
when called for example as "./factorize.py 123123" it gives the factorization
of the number 123123.
Python allows to write small programs
very fast. For example quadratic.py, produces
pseudorandom number generators using a quadratic iteration.
An example, of a python program which interacts with the user is the
klingon.py game.
Python is however also used for large projects on the web. The webserver
zope for example is written in python.
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| Links |
Books |
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- Martin C. Brown, Python Annotated Archives, Osborne
- Mark Lutz, David Ascher, Learning Python
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