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diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex index d7d363c..49f36b7 100644 --- a/Doc/tut/tut.tex +++ b/Doc/tut/tut.tex @@ -2014,6 +2014,49 @@ Here is a small example using a dictionary: 1 \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} + +When looping through a sequence, the position index and corresponding +value can be retrieved at the same time using the +\function{enumerate()} function. + +\begin{verbatim} +>>> for i, v in enumerate(['tic', 'tac', 'toe']): +... print i, v +... +0 tic +1 tac +2 toe +\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 |