Jython Essentials

Appendix E. Java-to-Python Quick Reference

This is a quick reference guide to the syntactic differences between Java and Python. It is not intended to provide full information on semantic differences between the two languages.

Basic Data Types

Python has a more limited set of numerical types than Java, but otherwise the two languages are similar. Python does not perform automatic conversions between types, however each basic type has a built-in function of the same name that attempts to convert the argument to that type.

Java	Python	Comment
boolean		Python has no specific Boolean type. False is represented by 0, and by any empty string, sequence, or mapping.
char	string	A character is just a string of length 1.
byte, short, int	int
long	long	A Python long has unbounded length.
float, double	float	Python floats have the same width as Java doubles.

Advanced Data Types

Python’s more advanced built-in types have more functionality and flexibility built into them than their Java equivalents.

Java	Python	Comment
java.lang.String	string
java.util.List	list
java.util.HashMap	dictionary
java.io.File	file	Python files contain much of the functionality of Java I/O streams.

Logical Operators

Python tends to use English words for its logical operators rather than symbols. Python has no equivalent to the Java operators ^ (binary XOR) and ?: (ternary conditional operator).

Java	Python	Comment
&&	and	Python operator always short circuits.
||	or	Python operator always short circuits.
!	not
==	is	Test for identical object identity.
equals( ...