Start learning Python-python variable types

Numbers (digital)

Numeric data types are used to store numeric values.

They are immutable data types, which means that changing the numeric data type assigns a new object.

int = Tenprint  int10

int = 20

print int

20

Python supports four different types of numbers:

• int (signed integral type)
• Long (longer integer [can also represent octal and hexadecimal])
• Float (float type)
• Complex (plural)

int	Long	float	Complex
10	51924361L	0.0	3.14j
100	-0x19323l	15.20	45.j
-786	0122L	-21.9	9.322e-36j
080	0xDEFABCECBDAECBFBAEl	32.3+e18	.876j
-0490	535633629843L	-90.	-.6545+0j
-0x260	-052318172735l	-32.54e100	3e+26j
0x69	-4721885298529l	70.2-e12	4.53e-7j

Long plastic mind directly with L, in case of mixing with the number 1

There are two types of plural definitions

#1 Complex
Copl=10+0.323232j

(10+0.323232J)

#2 complexcops=complex (10,0.3232j)
Print cops
(9.6768+0J)

Python string

A string or series (string) is a string of characters, consisting of numbers, letters, and underscores.

The Python string list has 2 order of values:

• Left-to-right index starts at default 0, with a maximum range of 1 less string lengths
• Right-to-left index starts with default-1, the maximum range is the beginning of the string

str="12312312"print str[0]        #  The first character in the output string print Str[2:5]      #  The string from the third to the fifth in the output string print str[2:]       #  Output a string starting from the third character print str        * # output two times

Python list

The list is the most frequently used data type in Python.

A list can accomplish the data structure implementation of most collection classes. It supports characters, numbers, and even strings that can contain lists (so-called nesting).

' 12321 ' ' Hi ' ]print list[0]            #  The first element of the output list print list[1:3]          #  Print list[2:]           #  output all elements from the third start to the end of the list print list

Python tuples

A tuple is another data type, similar to a list.

The tuple is identified with a "()". The inner elements are separated by commas. However, tuples cannot be assigned two times, which is equivalent to a read-only list.

' 1122 ' ' Hello ' )print tuple[0]            #  The first element of the output tuple print tuple[1:3]          # print tuple[2:]  # Output All elements from the third start to the end of the list print                Tinytuple * 2       #  output tuple two times

Python Meta Dictionary

The Dictionary (dictionary) is the most flexible built-in data structure type in Python, except for lists. 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.

The dictionary is identified with "{}". A dictionary consists of an index (key) and a value corresponding to it.

Dict ={}dict[' One'] ="Hello"dict[2] =" World" Printdict[' One']#the value of the output key is ' one 'PrintDICT[2]#the value of the output key is 2PrintDict#output a complete dictionaryPrintDict.keys ()#Output All keysPrintDict.values ()#Output All Values

Python Data type conversions

Sometimes, we need to convert the data-built type into the data type, and you just need to use the data type as the function name.

The following several built-in functions can perform conversions between data types. These functions return a new object that represents the value of the transformation.

function	Description
int (x [, Base])	Convert x to an integer
Long (x [, Base])	Convert x to a long integer
Float (x)	Convert x to a floating-point number
Complex (real [, Imag])	Create a complex number
STR (x)	Convert an object x to a string
REPR (x)	Convert an object x to an expression string
eval (str)	Used to evaluate a valid Python expression in a string and return an object
Tuple (s)	Converting a sequence s to a tuple
List (s)	Convert the sequence s to a list
Set (s)	Convert to mutable Collection
Dict (d)	Create a dictionary. D must be a sequence (key,value) tuple.
Frozenset (s)	Convert to immutable Collection
Chr (x)	Converts an integer to one character
UNICHR (x)	Converts an integer to a Unicode character
Ord (x)	Converts a character to its integer value
Hex (x)	Converts an integer to a hexadecimal string
Oct (x)	Converts an integer to an octal string

Start learning Python-python variable types