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diff --git a/lecture-notes/basic-python/slides/tuples_dicts_sets.tex b/lecture-notes/basic-python/slides/tuples_dicts_sets.tex new file mode 100644 index 0000000..b09fd99 --- /dev/null +++ b/lecture-notes/basic-python/slides/tuples_dicts_sets.tex @@ -0,0 +1,258 @@ +\section{Tuples} + +\begin{frame}[fragile] + \frametitle{Tuples -- Initialization} + \begin{lstlisting} + In[]: t = (1, 2.5, "hello", -4, "world", 1.24, 5) + In[]: t + \end{lstlisting} + \begin{itemize} + \item It is not always necessary to use parenthesis + \end{itemize} + \begin{lstlisting} + In[]: a = 1, 2, 3 + In[]: b = 1, + \end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Indexing} + \begin{lstlisting} + In[]: t[3] + In[]: t[1:5:2] + In[]: t[2] = "Hello" + \end{lstlisting} + \begin{itemize} + \item \alert{Tuples are immutable!} + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Swapping values} + \begin{lstlisting} + In[]: a = 5 + In[]: b = 7 + + In[]: temp = a + In[]: a = b + In[]: b = temp + \end{lstlisting} + \begin{itemize} + \item Here's the Pythonic way of doing it + \end{itemize} + \begin{lstlisting} + In[]: a, b = b, a + \end{lstlisting} + \begin{itemize} + \item The variables can be of different data-types + \end{itemize} + \begin{lstlisting} + In[]: a = 2.5 + In[]: b = "hello" + In[]: a, b = b, a + \end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Tuple packing \& unpacking} + \begin{lstlisting} + In[]: 5, + + In[]: 5, "hello", 2.5 + \end{lstlisting} + \begin{itemize} + \item Tuple packing and unpacking, when swapping + \end{itemize} + \begin{lstlisting} + In[]: a, b = b, a + \end{lstlisting} +\end{frame} + +\section{Dictionaries} + +\begin{frame}[fragile] + \frametitle{Creating Dictionaries} + \begin{lstlisting} + In[]: mt_dict = {} + + In[]: extensions = {'jpg' : 'JPEG Image', + 'py' : 'Python script', + 'html' : 'Html document', + 'pdf' : 'Portable Document Format'} + + In[]: extensions + \end{lstlisting} + \begin{itemize} + \item Key-Value pairs + \item \alert{ No ordering of keys! } + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Accessing Elements} + \begin{lstlisting} + In[]: print extensions['jpg'] + \end{lstlisting} + \begin{itemize} + \item Values can be accessed using keys + \end{itemize} + \begin{lstlisting} + In[]: print extensions['zip'] + \end{lstlisting} + \begin{itemize} + \item Values of non-existent keys cannot, obviously, be accessed + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Adding \& Removing Elements} + \begin{itemize} + \item Adding a new key-value pair + \end{itemize} + \begin{lstlisting} + In[]: extensions['cpp'] = 'C++ code' + In[]: extensions + \end{lstlisting} + \begin{itemize} + \item Deleting a key-value pair + \end{itemize} + \begin{lstlisting} + In[]: del extension['pdf'] + In[]: extensions + \end{lstlisting} + \begin{itemize} + \item Assigning to existing key, modifies the value + \end{itemize} + \begin{lstlisting} + In[]: extensions['cpp'] = 'C++ source code' + In[]: extensions + \end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Containership} + \begin{lstlisting} + In[]: 'py' in extensions + In[]: 'odt' in extensions + \end{lstlisting} + \begin{itemize} + \item Allow checking for container-ship of keys; NOT values + \item Use the \texttt{in} keyword to check for container-ship + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Lists of Keys and Values} + \begin{lstlisting} + In[]: extensions.keys() + In[]: extensions.values() + \end{lstlisting} + \begin{itemize} + \item Note that the order of the keys and values match + \item That can be relied upon and used + \end{itemize} + \begin{lstlisting} + In[]: for each in extensions.keys(): + ....: print each, "-->", extensions[each] + ....: + \end{lstlisting} +\end{frame} + +\section{Sets} + +\begin{frame}[fragile] + \frametitle{Creating Sets} + \begin{lstlisting} + In[]: a_list = [1, 2, 1, 4, 5, 6, 2] + In[]: a = set(a_list) + In[]: a + \end{lstlisting} + \begin{itemize} + \item Conceptually identical to the sets in mathematics + \item Duplicate elements not allowed + \item No ordering of elements exists + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Operations on Sets} + \begin{lstlisting} + In[]: f10 = set([1, 2, 3, 5, 8]) + In[]: p10 = set([2, 3, 5, 7]) + \end{lstlisting} + \begin{itemize} + \item Mathematical operations performed on sets, can be performed + \end{itemize} + \begin{itemize} + \item Union + \begin{lstlisting} + In[]: f10 | p10 + \end{lstlisting} + \item Intersection + \begin{lstlisting} + In[]: f10 & p10 + \end{lstlisting} + \item Difference + \begin{lstlisting} + In[]: f10 - p10 + \end{lstlisting} + \item Symmetric Difference + \begin{lstlisting} + In[]: f10 ^ p10 + \end{lstlisting} + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Sub-sets} + \begin{itemize} + \item Proper Subset + \begin{lstlisting} + In[]: b = set([1, 2]) + In[]: b < f10 + \end{lstlisting} + \item Subsets + \begin{lstlisting} + In[]: f10 <= f10 + \end{lstlisting} + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Elements of sets} + \begin{itemize} + \item Containership + \begin{lstlisting} + In[]: 1 in f10 + In[]: 4 in f10 + \end{lstlisting} + \item Iterating over elements + \begin{lstlisting} + In[]: for i in f10: + ....: print i, + ....: + \end{lstlisting} + \item Subsets + \begin{lstlisting} + In[]: f10 <= f10 + \end{lstlisting} + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Sets -- Example} + \begin{block}{} + Given a list of marks, \texttt{[20, 23, 22, 23, 20, 21, 23]} list + all the duplicates + \end{block} + \begin{lstlisting} + In[]: marks = [20, 23, 22, 23, 20, 21, 23] + In[]: marks_set = set(marks) + In[]: for mark in marks_set: + ....: marks.remove(mark) + + # left with only duplicates + In[]: duplicates = set(marks) + \end{lstlisting} +\end{frame} + |