Data types for Python

There are six standard data types in the Python3:

Number (numeric)
String (String)
List (lists)
Tuple (tuple)
Sets (collection)
Dictionary (dictionary)

1.Number (digital)

Python3 has the following number types:

• Integer (Int) -usually referred to as an integer or integral, is a positive or negative integer, with no decimal points. The Python3 integral type is not limited in size and can be used as a long type, so Python3 does not have a long type of Python2.
• float (float) -floating-point type consists of integral and fractional parts, and floating-point types can also be represented using scientific notation (2.5e2 = 2.5 x 102 = 250)
• complex numbers ((complex)) -complex numbers are composed of real and imaginary parts, and can be represented by a + BJ, or complex (a, b), where both the real and imaginary part of a complex number are floating-point types.

Python Numeric type conversions:

• int (x) converts x to an integer.

• float (x) converts the x to a floating-point number.

• Complex (x) converts x to a complex number, the real part is x, and the imaginary part is divided into 0.

• complex (x, y) converts x and y to a complex number, the real part is x, and the imaginary part is Y. X and y are numeric expressions.

Number = 235Print(Type (number))#View the type of number. ifIsinstance (number,dict):#determines whether a number is (int, float, bool, complex) type, or whether it is a (str,list,tuple,set,dict) type.     Print("is OK")Else:    Print("is no") Money= Input ("Enter Number:")ifMoney.isdigit ():#To determine if it is a number, money must be input.     Print("is OK")Else:    Print("is no")
‘‘‘
Isinstance (variable, type to be judged) #判断是否是要判断的类型
Variable. IsDigit () #判断是否为正整数

2.String (String)

The strings in Python are enclosed in single quotation marks (') or double quotation marks ("), and the special characters are escaped with a backslash (\).

The syntax for intercepting a string is as follows:

Variable [head subscript: Tail subscript]

String manipulation:

str ='Runoob'Print(str)#Output StringPrint(Str[0:-1])#outputs all characters from the first to the penultimatePrint(Str[0])#The first character of the output stringPrint(Str[2:5])#outputs the characters from the third start to the fifthPrint(str[2:])#output all characters from the beginning of the thirdPrint(STR * 2)#output String two timesPrint(str +"TEST")#Connection String

3.List (list)

A list can accomplish the data structure implementation of most collection classes. The types of elements in a list can be different, it supports numbers, and strings can even contain lists (so-called nesting).
A list is a comma-delimited list of elements written between square brackets ([]).
As with strings, lists can also be indexed and truncated, and a new list containing the required elements is returned when the list is truncated.

List = ['ABCD', 786, 2.23,'Runoob', 70.2]tinylist= [123,'Runoob'] Print(list)#Output Complete listPrint(List[0])#The first element of the output listPrint(List[1:3])#output from the second start to a third elementPrint(list[2:])#outputs all elements starting from the third elementPrint(Tinylist * 2)#output Two-time listPrint(List + tinylist)#Connection List

4.Tuple (tuple)

Tuple (tuple) is similar to a list, except that the elements of a tuple cannot be modified. Tuples are written in parentheses (()), and the elements are separated by commas.

Print (tuple)             # Output Full tuple Print (Tuple[0])          # the first element of an output tuple Print (Tuple[1:3])        # output starts from the second element to the third element Print (tuple[2:])         # outputs all elements starting from the third element Print (Tinytuple * 2)     # output two tuples Print # Connecting tuples

5.Sets (Collection)

A collection (set) is a sequence of unordered, non-repeating elements.
The basic function is to test the membership and remove duplicate elements.
You can create a collection using the curly braces {} or the set () function, note: Creating an empty collection must be set () instead of {}, because {} is used to create an empty dictionary.

Student = {' Tom ', ' Jim ', ' Mary ', ' Tom ', ' Jack ', ' Rose '}
Print (student) # output set, duplicate elements are automatically removed

# member Test
if (' Rose ' in student):
Print (' Rose in the collection ')
else:
Print (' Rose is not in the collection ')

# set can perform set operations
A = set (' Abracadabra ')
b = Set (' Alacazam ')

Print (a)
Difference set of print (A-B) # A and
The set of print (a | b) # A and B
Print (A & B) # intersection of # A and B
Print (a ^ b) # A and B do not exist in the same element

6.Dictionary (dictionary)

The Dictionary (dictionary) is another very useful built-in data type in Python.
A list is an ordered combination of objects, and a dictionary is a collection of unordered objects. The difference between the two is that the elements in the dictionary are accessed by keys, not by offsets.
A dictionary is a type of mapping that is identified by the dictionary with "{}", which is an unordered key (key): The value pair collection.
The key (key) must use the immutable type.
In the same dictionary, the key must be unique

Dict ={}dict[' One'] ="Www.w23.com"dict[2] ="Www.4dd.com"tinydict= {'name':'Runoob','Code': 1,'site':'www.runoob.com'}Print(dict[' One'])#the value of the output key is ' one 'Print(Dict[2])#the value of the output key is 2Print(tinydict)#output a complete dictionaryPrint(Tinydict.keys ())#Output All keysPrint(Tinydict.values ())#Output All Values

Data types for Python