Summary of Python basics notes
Tuples Tuple
It’s an immutable list. The contents and total amount cannot be modified. Use parentheses
tup1=(‘zhansan’,1992,’physics’)
Allows new tuples to be generated using tuple operators
(5, 6) + (8,9,10) = (5,6,7,8.9, 10)
(‘good’,’bye’)*2=(‘good’,’bye’,’good’,’bye’)
t=’b’,’c’=(‘b’,’c’)
The fetch data is exactly the same as the list
If a tuple holds a list, the contents of the list can be modified
If a tuple has only one element, you must add a comma after the element to indicate that it is a tuple.
List: Content allows for extended storage of dynamically changing inefficient runtime data when needed to change trial weather, stocks, and other data
Tuple: the content is immutable, fixed and constant, the highest efficiency of preserving stable and constant data, such as country name and element period
Sequence of the Sequence
An ordered queue is a common name for a class of data structures: string, list, tuple, number sequence (Range).
The contents of a numeric sequence are immutable and are created using the range() function
R = the range of 0-99 (0100) r [set] = [three, four, five]
R2 =range(0,20,2) 2 is the step size
The fipolassi sequence 1,1,3,5,8,13…
Conversions between sequence types
List () is converted to a list
Tuple () converts to a tuple
The STR () function is used to join lists by converting single data to a string join
Print (“”.join(LST)) “” all elements in the list must be strings
A collection of
Python built-in data structure, no value dictionary.
Features: unordered, non-repeating elements, variable, allows mathematical operations, scattered storage
Create {} or set() function create
The set() built-in function converts from other data structures
Cl =set()
Intersection: Get the duplicate parts of two sets and create a new set
C3 =c1. Intersection (c2) c1. Intersection_update (c2) intersection_update(C2
Union: To combine two sets for deduplication
C3 =c1. Union (c2) No union update function
Difference set: The difference part of two sets
C3 =c1.difference(c2) Sets of one-way differences between C1 and C2
C6 =c1. Symmetric_difference (c2) Bidirectional difference set C1 in C2 and c2 in C1
c1.difference_update(c2) .symmetric_difference_update
Relational operations between collections
S1. Issubset (s2) Determines whether S1 is a subset of S2.
S1. issuperset(s2) Checks whether S1 is the parent set of S2.
S1. isdisjoint(s2) Determines whether duplicate elements exist in two sets. True does not exist, False does exist
Add, delete, and change collections
C1.add (” jurisprudence “) adds an element if it does not exist, if it does ignore it
C1. Update (list | tuple) add multiple elements at a time
C1. remove(“yuansu”) removes an element, no element error is reported
C1.discard (“yuansu”) ignores non-existent elements
Python’s built-in generators
Generative syntax [appended data loop statement loop or judgment statement]
List generator
LST =[I *10 for I in range(10,20)]
Lst2 =[I *10 for I in range(10,20) if I % 2= = 0]
Dictionary generation
dict1={i+1:list[i] for i in range(0,len(lst5))}
Set generator
Set1 ={I *j for I in range(1,4) for j in range(1,4) if I ==j}
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