reduhq / data_structures.py

Data structures in python (Lists, Dictionaries, Tuples, Sets)

CONTENT

• DATA STRUCTURES
  • Lists
  • Tuples
  • Dictionaries
  • Sets
• METHODS
  • String Methods
  • List Methods
  • Dictionary Methods
  • Set Methods

DATA STRUCTURES

1. Lists:

   • Ordered sequence of elements.
   • Mutable: You can add, remove, or modify elements.
   • Defined using square brackets [ ].
   • Allows duplicates.

2. Tuples:

   • Ordered sequence of elements.
   • Immutable: Once created, they cannot be modified.
   • Defined using parentheses ( ).
   • Allows duplicates.

3. Dictionaries:

   • Associative data structure that stores key-value pairs.
   • Mutable: You can add, remove, or modify elements.
   • Defined using curly braces { }.
   • Does not allow duplicate keys, but values can be repeated.

4. Sets:

   • Unordered collection of unique elements.
   • Mutable: You can add or remove elements.
   • Defined using curly braces { } or the set() function.
   • Does not allow duplicate elements.

METHODS

STRING METHODS

NOTE: To see more list methods, visit Python String Methods

Method	Description	example
DIR	The dir() method returns the list of valid attributes of the passed object	dir(object)
UPPER	The upper() method returns a string where all characters are in upper case	my_string.upper()
LOWER	The lower() method returns a string where all characters are lower case	my_string.lower()
CAPITALIZE	The capitalize() method returns a string where the first character is upper case, and the rest is lower case	my_string.capitalize()
FIND	The find() method finds the first occurence of the specified value. The find() method returns -1 if the value is not found.	my_string.find("welcome")
INDEX	The index() method finds the first occurence of the specified value. The index() method rises an exception if the value is not found	my_string.("hello")
ISNUMERIC	The isnumeric() method returns True if all the characters are numeric (0-9), otherwise False	my_string.isnumeric()
ISALPHA	The isalpha() method returns True if all the characters are alphabeth letters (a-z). Example of characters that are not alphabet letters: (space)!#%&? etc.	my_string.isalpha()
COUNT	The count() method returns the number of times a specified value appears in the string	my_string.count("apple")
LEN	len() is a function that returns an integer which is the length of the string	len(my_string)
STARTSWITH	The startswith() method returns True if the string starts with the specified value, otherwise False	my_string.startswith("Hi")
ENDSWITH	The endswith() method returns True if the string ends with the specified value, otherwise False	my_string.endswith(".")
REPLACE	The replace() method replaces a specified phrase with another specified phrase	my_string.replace("bananas", "apples")
SPLIT	The split() method splits a string into a list	my_string.split(", ")

LIST METHODS

# LIST Creates a list
list(["hello", True, 25])
my_list = ["hello", True, 25]

NOTE: To see more list methods, visit Python List Methods

Method	Description	example
LEN	The len() function returns the number of items in a list	len(my_list)
APPEND	The append() method appends an element to the end of the list	my_list.append("hahaha")
INSERT	The insert() method inserts the specified value at the specified position	my_list.insert(2, "apple")
EXTEND	the extend() method adds the specified list elements (or any iterable) to the end of the current list	my_list.extend([False, 20])
POP	The pop() method removes the element at the specified position	my_list.pop(0)
REMOVE	The remove() method removes the specified item	my_list.remove("apple")
CLEAR	The clear() method removes all the elements from a list	my_list.clear()
SORT	The sort() method sorts the list ascending by default	my_list.sort(), my_list.sort(reverse=True)
REVERSE	The reverse() method reverses the sorting order of the elements	my_list.reverse()

DICT METHODS

# DICT Creates a dictionary
dict(name="Liam", age=25, city="Madrid")
my_dict = {
	"name": "Liam",
	"age": 25,
	"city": "Madrid"
}

NOTE: To see more dict methods, visit Python Dictionary Methods

Method	Description	example
KEYS	The keys() method returns a view object. The view object contains the keys of the dictionary, as a list.	my_dict.keys()
GET	The get() method returns the value of the item with the specified key, if the key doesn't exist, returns None	my_dict.get("name")
CLEAR	The clear() method removes all items from the dictionary	my_dict.clear()
POP	The pop() method removes the specified item from the dictionary	my_dict.pop("name")
ITEMS	the items() method is used to return the list with all dictionary keys with values	my_dict.items()

SET METHODS

# SET creates a set
set(["Luis", "Jilliam"])
my_set = {"Luis", "Jilliam"}

# Creating an inmutable set
frozenset(["Luis", "Jilliam"])

NOTE: To see more set methods, visit Python Set Methods

Method	Description	example
ISSUBSET	Return True if all items in set x are present in set y	my_set_x.issubset(my_set_y)
ISSUPERSET	Return True if all items set y are present in set x	my_set_x.issuperset(my_set_y)
ISDISJOINT	Return True if no items in set x is present in set y	my_set_x.isdisjoint(my_set_y)