Python Frequently Asked Questions Release 2.7.6 Guido van Rossum Fred L. Drake, Jr., editor November 10, 2013 Python Software Foundation Email:
[email protected] CONTENTS 1 General Python FAQ 1 1.1 General Information.........................................1 1.2 Python in the real world.......................................4 1.3 Upgrading Python..........................................6 2 Programming FAQ 9 2.1 General Questions..........................................9 2.2 Core Language............................................ 12 2.3 Numbers and strings......................................... 19 2.4 Sequences (Tuples/Lists)....................................... 23 2.5 Dictionaries.............................................. 26 2.6 Objects................................................ 28 2.7 Modules............................................... 32 3 Design and History FAQ 35 3.1 Why does Python use indentation for grouping of statements?................... 35 3.2 Why am I getting strange results with simple arithmetic operations?................ 35 3.3 Why are floating point calculations so inaccurate?......................... 35 3.4 Why are Python strings immutable?................................. 36 3.5 Why must ‘self’ be used explicitly in method definitions and calls?................ 36 3.6 Why can’t I use an assignment in an expression?.......................... 37 3.7 Why does Python use methods for some functionality (e.g. list.index()) but functions for other (e.g. len(list))?...........................................