Learn a few other languages. It will help you make the difference between algorithms (the structure of processing, unchanged between languages) and the local syntaxic features of the language. Then you can “write Foo in Bar” for any combination of languages “Foo” and “Bar”.

This is useful if you want to understand how to code to python in a more pythonic or correct way: http://www.python.org/dev/peps/pep-0008/

You could post your code at Refactor my code to see if someone can show you a more Pythonic way to do it.

You could start by reading The Zen of Python. It’ll give you some insight into how Python code is supposed to be written, provided you understand the language enough to understand what it’s talking about. 🙂

If you want to see some fairly idiomatic Python that does non-trivial stuff, there’s Dive Into Python, although Dive Into Python 3 is newer and might be a better source of style tips. If you’re looking more for some points to review, there’s Code Like a Pythonista.

Some of the major ways in which Python differs from C/Java-like languages are:

1. List comprehensions.

2. Support for functional programming.

3. The use of certain Pythonic constructs instead of similar C-like constructs although both seem to work (list comprehensions can be argued to be a part of this, but there are others).

There are others, but these are the main ones that bugged me when I first started Python (and I had come from years of Java like you).

Before using any of these, it is helpful to understand why you should go for pythonic code rather than the usual C/Java way in Python, although both give you the same output.

For starters, Python provides some powerful features not available in C/Java that makes your code much clearer and simpler (although this is subjective, and might not look any better to someone coming from Java at first). The first two points fall into this category.
For example, support for functions as first class objects and closures makes it easy to do things that would need all kinds of weird acrobatics with inner classes in Java.

But a major reason is that Python is an interpreted language, and certain constructs are much faster than the equivalent C/Java-like code. For example, list comprehensions are usually a lot faster than an equivalent for-loop that iterates over the indices of a list and accesses each item by index. This is a very objective benefit, and IMHO a lot of the “Python in way too slow” way of thinking comes from using Java-style code shoe-horned into Python.

One of the best ways to learn about pythonic code is to read other people’s code. I actually learnt a lot by looking at Python code posted in answers to SO questions. These often come with explanations and it is usually obvious why it is better than non-pythonic code (speed, clarity, etc.).

Edit:

Of course, there are other ways of getting other people’s code. You can also download and look through the code of any good open source Python project. Books are also a good resource, I would recommend O’Reilly Python Cookbook. It has lots of useful code examples and very detailed explanations.

Definitely not a panacea but I think you should try some code golf in Python. Obviously nobody should write “golfed” code IRL, but finding the most terse way to express something really forces you to exploit the built in functionality of the language.

If you are new to Python and coming from Java (or C#, or other similar statically typed OO language), these classic articles from PJ Eby and Ryan Tomayko are necessary reading:

• Python Is Not Java (PJE)
• Java is not Python, either (PJE)
• Python Interfaces are not Java Interfaces (PJE)
• The Static Method Thing (Tomayko)
• Getters/Setters/Fuxors (Tomayko)

Someone provided me with this list of how “Python is not Java” when I started Python after Java, and it was very helpful.

Also, check out this similar SO question that I posted a short time ago when in a similar position.

Eat Python, Sleep Python and Drink Python. That is the only way……..

Try to find algorithms that you understand well and see how they are implemented in python standard libraries.

Persist. 🙂

1) Python supports many (but not all) aspects of
object-oriented programming; but it is
possible to write a Python program without
making any use of OO concepts.

1) Java supports only object-oriented
programming.

2) Python is designed to be used interpretively.
A Python statement may be entered at the
interpreter prompt

(>>>)

, and will be executed
immediately. (Implementations make some
use of automatic compilation into bytecodes
(.pyc files).

2) Programs written in Java must be explicitly
compiled into bytecodes (.class files),
though an IDE may do this automatically in a
way that is transparent to the user. Java does
not support direct execution of statements –
though there are tools like Dr. Java that
support this.

3) Python is dynamically typed:
• A variable is introduced by assigning a
value to it. Example:

someVariable = 42

• A variable that has been assigned a value of
a given type may later be assigned a value
of a different type. Example:

someVariable = 42
someVariable = 'Hello, world'

3) Java is

statically typed

:
• A variable must be explicitly declared to be
of some type before assigning a value to it,
though declaration and assignment may be
done at the same time. Examples:

int someVariable;
int someVariable = 42;

• A variable that has been declared to be of a
particular type may not be assigned a value
of a different type.

4) Python supports the following built-in data
types:
Plain integers (normally 32-bit integers in
the range -2147483648 through
2147483647).
• Long integers (size limited only by memory
size of the machine running on)
• Booleans (False and True).
• Real numbers.
• Complex numbers.
In addition, Python supports a number of
types that represent a collection of values –
including strings, lists, and dictionaries.

4) Java has two kinds of data types: primitive
types and reference types. Java supports the
following primitive data types:
• byte – 8-bit integers
• short – 16-bit integers
• int – 32-bit integers
• long – 64-bit integers (Java also supports a
class java.math.BigInteger to represent
integers whose size is limited only by
memory)
• float – 32-bit real numbers.
• double – 32-bit real numbers.
• boolean – (false and true).
• char – a single character.
In addition, Java supports arrays of any type
as the reference types, and the API includes
the class String and a large number of classes
used for collections of values.

5)

Python is line-oriented:

statements end at the
end of a line unless the line break is explicitly
escaped with . There is no way to put more
than one statement on a single line.
Examples:
this is a statement
this is another statement
this is a long statement that extends over more
than one line

5)

Statements in Java always end with a
semicolon (;)

. It is possible for a statement to
run over more than one line, or to have
multiple statements on a single line.
Examples:
this is a statement;
this is another statement;
this is a long statement that extends over more
than one line;
a statement; another; another;

6)

Python comments begin with #

and extend to
the end of the line. Example:

This is a comment

A new statement starts here

6) Java has two kinds of comments. A comment
beginning with // extend to the end of the
line (like Python comments). Comments can
also begin with /* and end with */. These
can extend over multiple lines or be
embedded within a single line. Examples:

// This is a comment
A new statement starts here
/* This is also a comment */
/* And this is also a comment, which is
 long enough to require several lines
 to say it. */

Statement starts /* comment */ then continues

7) Python strings can be enclosed in either single
or double quotes (‘ or “”). A character is
represented by a string of length 1. Examples:

'This is a string'
"This is also a string" # Equivalent
'c' # A string
"c" # An equivalent string

Python uses the following operators for
constructing compound boolean expressions:

and, or and not. Example:
not(x > 0 and y > 0) or z > 0

7) Java strings must be enclosed in double
quotes (“”). A character is a different type of
object and is enclosed in single quotes (‘).
Examples:

"This is a String"
'c' // A character, but not a String
Java uses the following operators for
constructing compound boolean expressions:
&&, ||, ! and ^ (meaning exclusive or)
Example:
! (x > 0 && y > 0) || z > 0 ^ w > 0

8) In Python, the comparison operators

(>, <, >=, <=, == and !=) can be applied to numbers

,
strings, and other types of objects), and
compare values in some appropriate way (e.g.
numeric order, lexical order) where possible.

8) In Java, most of the comparison operators
( >, <, >=, and <=) can be applied only to
primitive types. Two (== and !=) can be
applied to any object, but when applied to
reference types they test for same (different)
object rather than same (different) value.

9) There is no universally-accepted Python
convention for naming classes, variables,
functions etc.

9) By convention, most names in Java use mixed
case. Class names begin with an uppercase
letter; variable and function names begin with
a lowercase letter. Class constants are named
using all uppercase letters with underscores.
Examples:
AClassName
aVariableName
aFunctionName()
A_CLASS_CONSTANT

10) Python definite looping statements have the
form for variable in expression: Example:

for p in pixels:
 something

10) Java has two kinds of definite looping
statements. One has the form

for (variable in collection) Example:
for (p in pixels)
 something;

11) Python uses the built-in function range() with
for to loop over a range of integers.
Examples:

for i in range(1, 10)
 something
(i takes on values 1, 2, 3, 4, 5, 6, 7, 8, 9)
for i in range(1, 10, 2)
 something
(i takes on values 1, 3, 5, 7, 9)

11) Java uses a different form of the for to loop
over a range of integers. Examples:

for (int i = 1; i < 10; i ++)
 something;
(i takes on values 1, 2, 3, 4, 5, 6, 7, 8, 9)
for (int i = 1; i < 10; i += 2)
 something;
(i takes on values 1, 3, 5, 7, 9)

12) Python conditional statements have the form
if condition: and an optional else part has the
form else:. The form elif condition: is
allowed as an alternative to an else:
immediately followed by an if. Examples:

if x < 0:
 something
if x < 0:
 something
else:
 something different
if x < 0:
 something
elif x > 0:
 something different
else:
 yet another thing

12) Java conditional statements have the form
if (condition) and an optional else part has
the form else (no colon) There is no elif
form – else if is used directly. Examples:

if (x < 0)
 something;
if (x < 0)
 something;
else
 something different;
if (x < 0)
 something;
else if (x > 0)
 something different;
else
 yet another thing;

13) The scope of a Python conditional or looping
statement is denoted by indentation. (If
multiple lines are to be included, care must be
used to be sure every line is indented
identically). Examples:

if x < 0:
 do something
do another thing regardless of the value of x
if x < 0:
 do something
 do something else
 do yet a third thing
do another thing regardless of the value of x

13) The scope of a Java conditional or looping
statement is normally just the next statement.
Indentation is ignored by the compiler
(though stylistically it is still highly desirable
for the benefit of a human reader). If
multiple lines are to be included, the scope
must be delimited by curly braces ({ , }).
(Optionally, these can be used even if the
scope is a single line.) Examples:

if (x < 0)
 do something;
do another thing regardless of the value of x;
if (x < 0)
do something; // Bad style-don't do this!
do another thing regardless of the value of x;
if (x < 0)
{
 do something;
 do something else;
 do yet a third thing;
}
do another thing regardless of the value of x;
if (x < 0)
{
 do something;
}
do another thing regardless of the value of x;