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| -rw-r--r-- | Doc/lib/libfuncs.tex | 12 | ||||
| -rw-r--r-- | Doc/tut/tut.tex | 43 |
2 files changed, 55 insertions, 0 deletions
diff --git a/Doc/lib/libfuncs.tex b/Doc/lib/libfuncs.tex index 3192a17..c7bb5a6 100644 --- a/Doc/lib/libfuncs.tex +++ b/Doc/lib/libfuncs.tex @@ -261,6 +261,18 @@ def my_import(name): \var{b}, and \code{0 <= abs(\var{a} \%{} \var{b}) < abs(\var{b})}. \end{funcdesc} +\begin{funcdesc}{enumerate}{iterable} + Return an enumerate object. \var{iterable} must be a sequence, an + iterator, or some other object which supports iteration. The + \method{next()} method of the iterator returned by + \function{enumerate()} returns a tuple containing a count (from + zero) and the corresponding value obtained from iterating over + \var{iterable}. \function{enumerate} is useful for obtaining an + indexed series: \code{(0, seq[0])}, \code{(1, seq[1])}, \code{(2, + seq[2])}, \ldots. + \versionadded{2.3} +\end{funcdesc} + \begin{funcdesc}{eval}{expression\optional{, globals\optional{, locals}}} The arguments are a string and two optional dictionaries. The \var{expression} argument is parsed and evaluated as a Python 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 |