list slice:
v[1:3]+ can also do third thing?
reverses???
v[::-1]Python get array size, size of other iterables, sets
map and filters run on iterable. also the loops? is a set an iterable?
+ conditional substitutions of lists in python
Python lists are dynamic arrays.
a = [1,2,3]Lists are mutable.
How to do each of following:
concatenation
slice/filter
insert
pop
traverse
map
sort
reverse
Eg the following defines a list, and then the second line returns that list.
my_list = [1,2,3]
[x for x in my_list]can do functions too. following returns [3,4,5]
[x + 2 for x in my_list]filter
[x for x in my_list if x >2]can be on any iterable:
[x for x in range(10)]filter
+ map function + lambda functions
a = (1,2,3)Tuples are immutable.
why not just use copy on write instead of tuples? + complex to implement?
why tuples broadly safety + mean that if create one tuple based on another, deep copy? if mutable + a=(1,2,3) + b=a + b[0]=2 * this fails, but if it didn’t we might get the following + print(a) * (2,2,3) + print(b) * (2,2,3)
with mutability can still do eg a=a[2] because this is creating a new thing and using it in name immutability means can’t do eg b[3] = 2 allows optimiser to assume not mutable. can cause speed ups