61A Lecture 22 Announcements Linked Lists Recursive Lists Can - PowerPoint PPT Presentation

61A Lecture 22

Announcements

Linked Lists

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) Global frame First Rest First Rest First Rest 1 2 3 s 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) Global frame First Rest First Rest First Rest 1 2 3 s Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 >>> t = s.rest Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 >>> t = s.rest >>> t.rest = s Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 >>> t = s.rest >>> t.rest = s >>> s.first Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 >>> t = s.rest >>> t.rest = s >>> s.first 5 Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 >>> t = s.rest >>> t.rest = s >>> s.first 5 >>> s.rest.rest.rest.rest.rest.first Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 >>> t = s.rest >>> t.rest = s >>> s.first 5 >>> s.rest.rest.rest.rest.rest.first 2 Note: The actual environment diagram is much more complicated. 4

Recursive Lists Can Change Attribute assignment statements can change first and rest attributes of a Link The rest of a linked list can contain the linked list as a sub-list >>> s = Link(1, Link(2, Link(3))) >>> s.first = 5 >>> t = s.rest >>> t.rest = s >>> s.first 5 >>> s.rest.rest.rest.rest.rest.first 2 Global frame First Rest First Rest Note: The actual 5 2 s environment diagram is much more complicated. t 4

Environment Diagrams

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): nonlocal bear if bear(berk) == 0: Return Value return [berk+1, berk-1] bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear if bear(berk) == 0: Return Value return [berk+1, berk-1] bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear bear if bear(berk) == 0: Return Value return [berk+1, berk-1] bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] if bear(berk) == 0: Return Value return [berk+1, berk-1] bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] f2: cal bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] f2: cal [parent=f1] bear = lambda ley: berk-ley return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] f2: cal [parent=f1] bear = lambda ley: berk-ley berk 2 return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): func λ (ley) [parent=f2] f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] f2: cal [parent=f1] bear = lambda ley: berk-ley berk 2 return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): func λ (ley) [parent=f2] f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] f2: cal [parent=f1] bear = lambda ley: berk-ley berk 2 return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6

Go Bears! Global frame def oski(bear): func oski(bear)[parent=G] oski def cal(berk): func λ (ley) [parent=f2] f1: oski [parent=G] nonlocal bear bear func abs(...) [parent=G] cal if bear(berk) == 0: func cal(berk) [parent=f1] Return Value return [berk+1, berk-1] f2: cal [parent=f1] bear = lambda ley: berk-ley berk 2 return [berk, cal(berk)] Return Value return cal(2) oski(abs) Return Value Return Value 6