Python Learning note 02 python data type 2

The main difference between a list and a tuple is that the list is enclosed in parentheses ([]) and their elements and sizes can be changed, while tuples are in parentheses () and cannot be updated. Tuples can be thought of as read-only lists.

Values stored in a list can be accessed using the slice operator ([] and [:]) with the index starting at 0, at the beginning of the list and ending with-1. The plus sign (+) symbol lists the join operator, and the asterisk (*) repeats the operation.

A python dictionary is a hash table type. They are made up of key-value pairs like associative arrays or hashes in Perl. The dictionary key can be almost any Python type, but it is usually a number or a string. The value can be any Python object.

The dictionary is composed of curly braces ({}), which can be assigned a value and accessed with square brackets ([]).

Sometimes, you might need to perform a conversion between built-in types. Conversions between types, simply use the class masterpiece as a function.

There are several built-in features that convert from one data type to another. These functions return a new object that represents the converted value.

Data type conversions:

function	Description
int (x [, Base])	Converts x to an integer. The cardinality is specified as base, if X is a string.
Long (x [, Base])	Converts x to a long integer. The cardinality is specified as base, if X is a string.
Float (x)	Converts an X to a floating-point number.
Complex (real [, Imag])	Creates a complex number.
STR (x)	Convert object x to a string representation.
REPR (x)	Object x is converted to an expression string.
eval (str)	Computes a string and returns an object.
Tuple (s)	Converts s to a tuple.
List (s)	Convert s to a list.
Set (s)	Converts s to a collection.
Dict (d)	Create a dictionary. D must be the (key, value) tuple sequence.
Frozenset (s)	Converts s to frozen set.
Chr (x)	Integers are converted to one character.
UNICHR (x)	The integer is converted to a Unicode character.
Ord (x)	Converts a single character to an integer value.
Hex (x)	Converts an integer to a hexadecimal string.
Oct (x)	Converts an integer into a eight-based string.

Python Learning note 02 python data type 2