CH 3 - DATA HANDLING (Module 4) Flashcards
python built in core data types
- numbers
- strin
- list
- tuple
- dictionary
numbers (types)
- integers
i. integers (signed)
ii. booleans - floating point numbers
- complex numbers
bool(0)
false
bool(1)
true
floatin point numbers advantages over inteers
- they can represent values between inteer
2 wider range of numbers it can represent
disadvantae of floatin point number
they are slower than inteer operations
python respresents complex numbers in what form
A + Bj
a = 0 + 3.1j
b = 1.5 + 2j
why is j symbol used to represent complex number i
z = 2.5 + 3.9j
print(z.real) and print(z.imag)
2.5 and 3.9
python index or subscript
the numbered position of a letter in the string
- a python string is a sequence of characters and each character can be accessed using its index
- strings in python are stored as INDIVIDUAL CHARACTERS in contiguous location with TWO WAY INDEX for EACH LOCATION
python indices length
python indices begin 0 onwards in forward direction and -1, -2 in backward direction
- the length of python index of any string from forward would be lenth-1 since index starts from 0
are strings immutable or mutable
IMMUTABLE
how are strings immutable
- you cannot change the individual letters of a string in place by assignment because STRINS ARE IMMUTABLE
- hence, ITEM ASSINMENT IS NOT SUPPORTED
for ex:
name = “hello”
name[0] = “p”
error aayega
lists [1, 2, 3]
lists in python represent a list of comma separated values of any datatype between square brackets
are lists immutable or mutable
mutable
a = [1, 2, 3] chane 1 to 10 in th elist
a [0] = 10
print(a)
a = [10, 2, 3]
tuples ( )
represented as a roup of comma separated values of any data type with paranthesis/ brackets
are lists immutable or mutable
immutable
sets
similar to lists that can store multiple values same as mathematical sets
differences bw sets and lists
sets lists
{ } [ ]
unordered and unindexed
doesnt allow duplicate entries
cannot contain mutable elements
SIMILARITY: BOTH ARE MUTABLE THO
what deos it mean that sets cannot CONTAIN mutable elements
a list cannot exist inside a set
ex: { 1, 2, [3, 4] } = 3,4 is a list which is written inside set
however, a tuple CAN BE CONTAINED inside a set since a tuple is immutable
ex: { 1, 2, (3, 4)
are sets immutable or mutable
MUTABLE
even thouh it cannot contain mutable elements, it is MUTABLE
dictionary
it is an unordered set of comma sepaqrated key: value pairs within { }
- no keys can be the same in a dictionary
- THERE ARE UNIQUE KEYS IWTHIN A DICTIONARY
everything is a ______ in python
object: it is an entity that has certain properties and that exhibit a certain type of behaviour
- python calls every entity that stores any values or any type of data as an object
- cuz python is an object oriented language
- strins, tuples, lists, dictionaries (all data types), inteers, numbers, variables are all objects
id function?
the id function when you use on any data value or variable, it returns the unique identity of the object, which is its assigned memory address
mutability means
it means that in same memory address, new value can be stored as in when you want.
-the types that do not support this property are immutable type data objects
exs of immutable type data objects
inteers floatin point nos booleans strins tuples
mutable type data objects in python are
list
dictionaires
sets
unicode code or lexicoraphical code
the ordinal values of the characters
ordinal code of small alphabets is reater than those of capital alphabets
a > A
97 > 65
EQUALITY AND IDNTITY (is) IMPORTANT REATION
1. If a IS b = TRUE then, a == b However, 2. If a ==b a IS b need not be true
