Data types for Python

Python's core data types are numeric types, string types, list types, tuple types, dictionary types, file types, and other types, including collection types, class types, and none.

One, the number---immutable type

1. include int,long,float,complex

2.python of digital literals

Boolean type

Full type

Long integer type

Floating point number

Plural

3. Digital operation

+-*/Subtraction

Truncate DIVISION

* * exponentiation

% modulus

-X Unary Subtraction

+X One-dollar addition

4. Comparison operations

<< left Shift

>> Right Shift

& Bitwise AND

| bitwise OR

^ bitwise-With OR

~ Bitwise REVERSE

Second, sequence type

1. Sequence type

Sequence represents an ordered collection of objects that are indexed as non-negative integers

Lists and tuples are sequences of arbitrary Python objects

The character and metacharacters group belongs to an immutable sequence, and the list supports inserting, deleting, and replacing elements

All sequences support iterations

Applicable to all sequences of operations and methods

S[i] Index operator

S[I:J] for slice operator, s[i:j:sides] Extended slice

--the result of slicing produces a new memory object

Min (s) max (s) is used only for sequences that can be sorted on elements

Sum (s[, START]) applies only to the sequence of numbers

Number of elements in lens (s) s

All (s) to check if all items in s are true

Any (s) to check if any of the items in S are true

Variable Unpacking v1,v2,....=s

2. string---A sequence of characters

A. Character type

String literals: Put text in single quotes, double quotes, and three quotation marks (three quotation marks can be implemented across lines, and special characters are entered)

Cannot support international character set ( if Unicode encoding is used, the character U is used before the character, such as U "Laizetian")

Document string

The first statement of a module, class, or function is a character, and the string becomes a document document string, which can be called using the __doc__ property.

B. Manipulation of strings

byte string: Byte (8bit data) sequence

Unicode string: Unicode character (16bit data) sequence

--Python can save Unicode characters using 32bit integers, but this is an option

Operation:

S.captitalize first character uppercase

S.index (Sub [, Start [, end]]) finds the location of the first occurrence of the specified string

S.join (t) using S as a delimiter to concatenate strings in a sequence T

S.lower () converted to lowercase

S.replace (old, new[, Maxreplace]) Replace a substring

S.split ([Seq[,maxsplit]]) uses Sep as a delimiter to divide a string, Maxsplit is the maximum number of partitions

S.strip ([chrs]) Delete chrs opening and closing blanks or characters

S.upper () build a string into uppercase

3. List-- container type

A. An ordered set of arbitrary objects, accessing the elements through an index, is a mutable object, heterogeneous, arbitrarily nested

B. Support in situ modification--Modify references

---Modify the specified index element, modify the developed Shard, delete the statement, built-in method

C. Operation:

list addition L1+L2---- will not be modified in place, return a new list directly

L1*n L1 repeats n times---- Returns a new list

In----Member relationship qualifier, usage item in container

Not in

List parsing----[functions]: Generating a list

How to copy a list

l1=[1,1,1] L2=L1------ID Same

Import Cory L2=copy.deepcopy (L1)

l2=l1[:]

4. Tuple tuples

A.

Symbol expression ()

Container type: An ordered set of arbitrary objects that access the elements through an index, immutable objects, fixed lengths

Supports heterogeneous, nested

B. Operation

Define an empty tuple ()----() to omit

Tuple add +: Create a new tuple

T1*n repeat Operation N Times

in<----> not in

The tuple itself is immutable, but if a tuple has nested elements of a mutable type (such as a list), modifications to such elements do not return a new tuple

Third, the dictionary dict

1. Overview

Unordered data collection, also known as associative arrays or hash lists in other spur languages

Element access via key

Variable type container, variable length, supports heterogeneous, nested

2. Form

{Key1:value1,k2:v2,k3:v3 ...}

{} Empty Dictionary

3. Operation

Dictionary copy: d2=d1.copy (different ID)

Quick Build Dictionary: dict (' 123 ', ' XYZ ')

Returns an Iterator object:

D1.iteritems ()

I1=d1.itervaluse () I1.next ()----shown individually

I1=d1.iterkeys () I1.next ()----shown individually

I1=d1.iteritems () I1.next ()----shown individually

Iv. Collection

1. Overview

A collection is a set of unordered values that can be hashed

Support for set-relationship testing

Member relationship tests: in,not in, Iteration

index, element Fetch, slice not supported

Type of collection:set,frozenset

There is no specific syntax format, only the factory function can be created

2. Methods and operations for collection types

Len (s) returns the number of items in S

C.copy () make a copy of S

S.difference (t) differential set, returning all items in S, but not in T

S.intersection (t) to intersect, returning all items in S and T

S.isdisjoint (t) returns True if S and t do not have the same item

S.issubset (t) returns True if S is a subset of T

S.issuperset (t) returns True if S is a superset of T

S.symmetric_difference (t) to find the symmetric difference set, return the item in s or T, but not in both sets

s.union (t) to return an item in S or T.

Collection operations

s | T----The set of S and T

The intersection of S & T----s and T

S-T---- seek the intersection

s^ t---- symmetry intersection

Len (s)----The number of items in the collection

Max (s)---- maximum value

MIN (s)---- minimum value

S1.add (' Lai ') can take a string as an entire set of elements

This article is from the "A-filled blog" blog, please be sure to keep this source http://laizetian.blog.51cto.com/10728827/1698761

Data types for Python