Python Advocacy


Why Python is a Great Language to Learn?

Yusuke Shinyama


Clean and Visible Structure

Python recognizes blocks by indentation. (No worry, you will love it.)

# Simple implementation of 

Mint problem.

# Define constants.
INF = 99999
denom = [1, 5, 10, 25, 50]

# Initialize the table.
table = [0] * 100

# Recursively compute the number of coins needed
for exact change: can't make change for negative numbers; no change
for 0; otherwise recurse.
def coins(n):
  if n < 0:
    return INF
  elif n == 0:
    return 0
  else:
    if table[n] == 0:
      table[n] = min([ coins(n-d) for d in denom ]) + 1
    return table[n]

# Sample run
print coins(77)
print [ coins(i) for i in range(1,100) ]

Functions can Return Multiple Values

# Return the quotient and the remainder at once.
def div(x, y):
  quotient = int(x / y)
  remainder = x % y
  return (quotient, remainder)

# Assign two values to different variables.
(q, r) = div(33, 5)

print q
print r

Elegant String/List Handling

Strings and Arrays can be handled in the same syntax.
a = "0 p 1 y 2 t 3 h 4 o 5 n 6"

Interactive Features

Python has nice interactive features (Bash-like line editing, function completion and history), which make it easy to play with built-in functions and libraries. It also includes online help function for almost every function in the library.

Here is a sample session:

$ python
Python 2.3.3 (#1, Feb  1 2004, 23:04:28)
[GCC 2.96 20000731 (Red Hat Linux 7.1 2.96-98)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> fp=file("/etc/hosts") (get a file object first)
>>> fp. (press Tab key here, it tries to expand the available methods)
fp.__class__         fp.__new__           fp.closed            fp.newlines          fp.softspace
fp.__delattr__       fp.__reduce__        fp.encoding          fp.next              fp.tell
fp.__doc__           fp.__reduce_ex__     fp.fileno            fp.read              fp.truncate
fp.__getattribute__  fp.__repr__          fp.flush             fp.readinto          fp.write
fp.__hash__          fp.__setattr__       fp.isatty            fp.readline          fp.writelines
fp.__init__          fp.__str__           fp.mode              fp.readlines         fp.xreadlines
fp.__iter__          fp.close             fp.name              fp.seek
>>> fp.read (press Tab again)
fp.read       fp.readinto   fp.readline   fp.readlines
>>> help(fp.readline) (view the online help of this method)
Help on built-in function readline:

readline(...)
    readline([size]) -> next line from the file, as a string.

    Retain newline.  A non-negative size argument limits the maximum
    number of bytes to return (an incomplete line may be returned then).
    Return an empty string at EOF.

>>> fp.readline() (try using it)
'127.0.0.1 localhost\n'
>>>

Python Types


References


Yusuke Shinyama