Python Data Types Flashcards
Numeric Types
Int, Float, Complex
Int
Ints are considered a primitive scalar type
Ints allow for unlimited precision (as many digits as you need)
Integers are always rounded towards zero
int(3.9) = 3
int(-3.9)=-3
float
float = floating point number
any number containing a decimal is interpreted as a float in python
None
None = null object (represents the absence of a value)
We can assign a value as None using the assignment operator: a = None
We can test if something is None using the “is” operator
a is none // True
bool
bool = boolean objects (True / False)
represents logical states and play an important role in Python control flow structures
str
str = string
this is a collection type
strings are sequences of chars
strings are IMMUTABLE meaning once you have constructed a string, you cannot modify its contents
tuple
( )
a tuple is a collection
a tuple is:
- ordered
- immutable (we cannot add or remove items)
- allows duplicates
similar syntax to lists, but they use parentheses
set
{ }
A set is a collection
sets are
- unordered
- unindexed
- mutable
- no duplicates
items within a set are unchangeable, but you can remove items and add new ones
A common use for a set is to remove duplicate items from a series of objects
list
[ ]
A list is a collection
Lists are:
- ordered
- mutable
- allow duplicate values
- indexed
range
range = a sequence representing an arithmetic progression of integers, generated by calls to the range constructor
range determines what it’s arguments mean by counting them
one arg = range(stop)
two arg = range(start, stop)
three args = range(start, stop, step)
dict
{ }
dicts are a mapping type
store values as key-value pairs
- iterable
- keys are immutable, unique (strings, numbers, tuples)
- values are mutable
as of Python 3.7, dicts are ordered
Primitive
Non-Primitive
Immutable
Sequence
Type of Collection (there are three: sequence, set, mapping)
Ordered
It’s elements can be accessed using a numeric index
examples: lists, tuples, ranges
Mapping
Type of Collection (there are three: sequence, set, mapping)
stores data in key-value pairs
ordered
example: dict
Set
{ }
Type of Collection (there are three: sequence, set, mapping)
- Unordered
- Immutable
- comprised of unique objects
Collection
A collection is an object that has zero or more member objects, called elements
Categories of collections:
1. sequences (list, tuple, range)
2. mappings (dict)
3. sets (set, frozenset)
Text Sequence
Strings and other text sequences are not considered collections
however, they are very similar to sequence collections
example: str
Literal
A literal is a syntactic notation that lets you directly represent an object in source code
they are constants that are directly written into the code and don’t need to be computed or evaluated
You can use literals to represent most data type values
Numeric
Numeric values represent numbers
integers and floats are both numeric values
