Parsing files with Python

Question

What type of Python objects should I use to parse files with a specific syntax? Also what sort of loop should be followed to make it through the file. Should one pass be sufficient? Two, three?

Answer 1

how complex the syntax is? are you inventing a new one or not?

for a complex language, consider bison bindings like lex + pybison.

if you can decide what syntax to use, try YAML.

Answer 2

You should offer more information about your aims ...

• What kind of file
• What structure? Tab separated? XML - like?
• What kind of encoding?
• Whats the target structure?
• Do you need to reparse the file in a regular time period (like an interpreter)?

Answer 3

It does not depend on your programming language (python) if your parser will have one, two, three or n passes. It depends on the grammar of the syntax you are trying to parse.

If the syntax is complex enough I would recommend LEX/YACC combo as Francis said.

Answer 4

It depends on the grammar. You can use pyparsing instead of implementing your own parser. It is very easy to use.