LAB_day 4

Sequences & Lists

-   sequence : an ordered collection of values

-   list : a sequence of values of any data type

List Basics

-   lists are denoted by []

-   features of lists:

( index ) : a position of an element in a list

: starts from 0 goes to (length -1)

:use list_name[index] to find the element in that index

For loops

-   similar to while loops

python codes ex.

def while_print_list(lst):

   index = 0

   while index < len(list)

      print(lst[index])

      index += 1

def for_print_list(lst):

   for elem in lst:

      print(elem)

List comprehension

-   compact way to create a list

python codes ex.

result = []

for elem in lst:

   if elem > 3:

      result += [elem + 1]

[elem+1 for elem in lst if elem > 3]

elem + 1 : output adding to the resulting list

lst : sequence we're iterating through

if elem > 3 : (optional) condition

Data Abstractions

-   treating codes as objects

-   you do not have to know how the code is implemented you just have to know what it does

-   data abstracted values are called Abstract Data Type

-   comprehension of data abstraction

: constructors _ create ADT

: selectors _ select values from ADT