From 66d8b27ce78f92f0dd2407a8f13f7591d9e3201d Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Sat, 5 Oct 2002 05:14:19 +0000 Subject: [PATCH] Backport 1.160 on looping idioms. Excludes enumerate(), a Py2.3 feature. --- Doc/tut/tut.tex | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex index a9ae9b41cb5a..0d4a1f240ea2 100644 --- a/Doc/tut/tut.tex +++ b/Doc/tut/tut.tex @@ -2046,6 +2046,35 @@ pattern, list comprehensions can compactly specify the key-value list. \end{verbatim} +\section{Looping Techniques \label{loopidioms}} + +When looping through dictionaries, the key and corresponding value can +be retrieved at the same time using the \method{items()} method. + +\begin{verbatim} +>>> knights = {'gallahad': 'the pure', 'robin': 'the brave'} +>>> for k, v in knights.items(): +... print k, v +... +gallahad the pure +robin the brave +\end{verbatim} + +To loop over two or more sequences at the same time, the entries +can be paired with the \function{zip()} function. + +\begin{verbatim} +>>> questions = ['name', 'quest', 'favorite color'] +>>> answers = ['lancelot', 'the holy grail', 'blue'] +>>> for q, a in zip(questions, answers): +... print 'What is your %s? It is %s.' % (q, a) +... +What is your name? It is lancelot. +What is your quest? It is the holy grail. +What is your favorite color? It is blue. +\end{verbatim} + + \section{More on Conditions \label{conditions}} The conditions used in \code{while} and \code{if} statements above can -- 2.47.3