list and dic added

Author: lev epshtein

data-types/list_tuples_sets/list_tuples_sets.py

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+# Lists are mutable sequences
+# https://docs.python.org/3/library/stdtypes.html#lists
+
+# 1 print list, len, access
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# print(courses)
+# print(len(courses))
+# print(courses[0])
+# print(courses[1])
+# print(courses[-2])
+# print(courses[-1])
+
+# 2 slicing:
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# print(courses[:2])
+# print(courses[2:])
+# print(courses[1:3])
+
+# 3 list append, insert
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# courses_2 = ["Dance","Poetry"]
+# print(courses)
+# courses.append(courses_2)
+# print(courses)
+
+# courses.insert(2,"Music")
+# print(courses)
+
+
+# 4 list remove , pop
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# print(courses)
+# courses.remove("History")
+# print(courses)
+#
+# pop_value = courses.pop()
+# print(courses)
+# print(pop_value)
+# pop_value = courses.pop(0)
+# print(pop_value)
+# print(courses)
+
+# 5 list reverse, sort
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# nums = [1,5,2,8,4,6]
+# print(courses)
+# courses.reverse()
+# print(courses)
+
+# courses.sort()
+# print(courses)
+# courses.sort(reverse=True)
+# print(courses)
+
+# print(sorted(nums))
+# print(nums)
+
+
+# list min, max, sum
+# nums = [1,5,2,8,4,6]
+# print(max(nums))
+# print(min(nums))
+# print(sum(nums))
+
+
+# 6 list index
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# print(courses.index("CompSci"))
+
+# in operator
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# print('Math' in courses)
+# print('Art' in courses)
+#
+# for item in courses:
+#     print(item)
+
+# for index, course in enumerate(courses, start=1):
+#     print(index, course)
+
+# 7 join, split
+# courses = ['History', 'Math', 'Physics', 'CompSci']
+# course_str = ', '.join(courses)
+# print(course_str)
+#
+# new_list = course_str.split(', ')
+# print(new_list)
+
+### Tuples immutable sequence types ###############
+# Mutable
+# list_1 = ['History', 'Math', 'Physics', 'CompSci']
+# list_2 = list_1
+#
+# print(list_1)
+# print(list_2)
+#
+# list_1[0] = 'Art'
+#
+# print(list_1)
+# print(list_2)
+
+
+# Immutable can't append remove etc but rest same as list
+# tuple_1 = ('History', 'Math', 'Physics', 'CompSci')
+# tuple_2 = tuple_1
+#
+# print(tuple_1)
+# print(tuple_2)
+#
+# tuple_1[0] = 'Art'
+#
+# print(tuple_1)
+# print(tuple_2)
+
+### Sets unordered and have no duplicates sequences ###############
+# Sets optimazed for in
+# cs_courses = {'History', 'Math', 'Physics', 'CompSci'}
+# print(cs_courses)
+# print('Math' in cs_courses) # optimazed for sets !
+
+# art_courses = {'History', 'Math', 'Art', 'Design'}
+# print(cs_courses.intersection(art_courses)) # both in sets
+# print(cs_courses.difference(art_courses)) # differnets between two
+# print(cs_courses.union(art_courses)) # union of both
+
+# empty initialitation
+# Empty Lists
+# empty_list = []
+# empty_list = list()
+#
+# # Empty Tuples
+# empty_tuple = ()
+# empty_tuple = tuple()
+#
+# # Empty Sets
+# empty_set = {} # This isn't right! It's a dict
+# empty_set = set()

dictionaries/dictionary_explanation.py

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+# Dictionaries are sometimes found in other languages as “associative memories” or “associative arrays”.
+# Unlike sequences, which are indexed by a range of numbers, dictionaries are indexed by keys, which can be any immutable type;
+# strings and numbers can always be keys. Tuples can be used as keys if they contain only strings, numbers, or tuples;
+# if a tuple contains any mutable object either directly or indirectly, it cannot be used as a key.
+# You can’t use lists as keys, since lists can be modified in place using index assignments, slice assignments, or methods like append() and extend().
+# https://docs.python.org/3/tutorial/datastructures.html#dictionaries
+
+# 1 Initialization , key, value. access
+# student = {'name': 'Jhon', 'age':'25', 'courses':['Math', 'CompSci']} # key can be int , string all immutable types !
+# print(student['name'])
+# print(student['courses'])
+#
+# print(student.get('phone', 'Not Found'))
+
+# 2 add key value
+# student = {'name': 'Jhon', 'age':'25', 'courses':['Math', 'CompSci']} # key can be int , string all immutable types !
+# student['phone'] = '555-55556'
+# print(student)
+# student['name'] = 'Janet'
+# print(student)
+
+# 3 dictionary update
+# student = {'name': 'Jhon', 'age':'25', 'courses':['Math', 'CompSci']} # key can be int , string all immutable types !
+# print(student)
+# student.update({'name': 'Jane', 'age':23, 'phone': '555-55556'})
+# print(student)
+
+# 4 dictionary del method
+# student = {'name': 'Jhon', 'age':'25', 'courses':['Math', 'CompSci']} # key can be int , string all immutable types !
+# print(student)
+
+# with del
+# del student['age']
+# print(student)
+
+# with pop
+# age = student.pop('age')
+# print(age)
+# print(student)
+
+
+# walking through dic
+# student = {'name': 'Jhon', 'age':'25', 'courses':['Math', 'CompSci']} # key can be int , string all immutable types !
+# print(len(student))
+# print(student.keys())
+# print(student.values())
+# print(student.items())
+
+# walking throught key
+# for key in student:
+#     print(key)
+
+# walking both key, values
+# for key, value in student.items():
+#     print(key,value)