DSAL Quiz Review - Python Data Structures

Practice flashcards covering Python data structures including tuples, map/lambda, file handling, sets, 2D lists, dictionaries, and arrays based on the DSAL Quiz Review.

Tuples

Immutable data structures in Python that do not support item assignment; attempting to modify an element directly will raise a TypeError.

map() function

A function that applies a given function, often a lambda, to every item in one or more iterables; for example, applying "pre_ " to words using map(lambda\,w:\,\text{"pre_ "}\,+\,w,\,words).

File Closing

A mandatory practice in file handling that ensures any pending changes are saved and frees up system resources for other processes.

symmetric_difference()

A set method that returns a new set containing elements that are in either Set A or Set B, but excludes elements that are common to both.

popitem()

A dictionary method that removes and returns an arbitrary (key, value) pair from the dictionary.

Slice Assignment

A list operation, such as $LstA[1:3]\,=\,[4, 5, 6]$, that replaces a range of elements and has the capability to change the total length of the list.

Array Type Consistency

A requirement of the Python array module where all elements must be of the same data type; adding a string to an integer array will raise a TypeError.

get() method

A dictionary method used to retrieve a value for a specific key, such as $grades.get("David",\,0)$, which prevents an error if the key is missing from the dictionary.

File Mode "r+"

A file handling mode that allows the user to read existing content and update or write to the file without erasing the current contents.

File Mode "x"

An exclusive creation mode in file handling that allows the creation of a new file but raises an error if the file already exists.

Set Unique Storage

The property of sets to store only unique elements; adding a duplicate value through methods like $add()$ or $update()$ will not increase the set's length.

Row Retrieval in 2D Lists

The process of accessing a specific nested list within a matrix, such as using $matrix[2]$ to retrieve the entire third row.

Element Retrieval in 2D Lists

Accessing a specific value within a matrix using double indexing, where $matrix[1][1]$ identifies the element at the second row and second column.

Dictionary copy() method

A method that creates a shallow copy of a dictionary, ensuring that changes made to keys in the new copy, such as $d2["x"] = 10$, do not affect the original dictionary.

Column Extraction

The use of list comprehension, such as $column\,=\,[row[2]\,for\,row\,in\,matrix]$, to create a new list from a specific vertical index across all rows.

array.array('f', …)

A specialized data structure that stores numeric floating-point values and requires that any appended items also be of type float.

Tuple with Mutable Objects

A scenario where a tuple contains a list, such as $(1, 2, [3, 4])$; while the tuple itself is immutable, the inner list can still be modified using methods like $append()$.

Reference vs. Copy Assignment

The distinction in list handling where $lst2val = lstval$ creates a reference to the same object, while $lst2val = lst2val + [5]$ creates a entirely new list object.