| What is Python? |
| --------------- |
| |
| Python is an interpreted, interactive, object-oriented programming |
| language. It incorporates modules, exceptions, dynamic typing, very |
| high level dynamic data types, and classes. Python combines |
| remarkable power with very clear syntax. It has interfaces to many |
| system calls and libraries, as well as to various window systems, and |
| is extensible in C or C++. It is also usable as an extension language |
| for applications that need a programmable interface. Finally, Python |
| is portable: it runs on many brands of UNIX, on the Mac, and on |
| MS-DOS. |
| |
| As a short example of what Python looks like, here's a script to |
| print prime numbers (not blazingly fast, but readable!). When this |
| file is made executable, it is callable directly from the UNIX shell |
| (if your system supports #! in scripts and the python interpreter is |
| installed at the indicated place). |
| |
| #!/usr/local/bin/python |
| |
| # Print prime numbers in a given range |
| |
| def main(): |
| import sys |
| min, max = 2, 0x7fffffff |
| if sys.argv[1:]: |
| min = int(eval(sys.argv[1])) |
| if sys.argv[2:]: |
| max = int(eval(sys.argv[2])) |
| primes(min, max) |
| |
| def primes(min, max): |
| if 2 >= min: print 2 |
| primes = [2] |
| i = 3 |
| while i <= max: |
| for p in primes: |
| if i%p == 0 or p*p > i: break |
| if i%p <> 0: |
| primes.append(i) |
| if i >= min: print i |
| i = i+2 |
| |
| main() |