1.Python what type of data? ?
There are five standard Python data types:
- Numbers (Digital)
- String (String)
- List (list) symbol []
- Tuple (tuple) symbol () ---- tuple not secondary assignment corresponding to read-only list.
- Dictionary (dictionary) corresponding to the key hash values among java
2.Python digital
Python supports four different types of numbers:
- int (signed integer)
- long (long integer [may also represent octal and hexadecimal])
- float (float)
- complex (plural)
3.Python string
Strings or string (String) is a string of characters consisting of numbers, letters, the underscore.
List of strings python are two kinds of values in this order:
- The default start index 0 from left to right, the maximum range is a little string length
- Index of default from right to left at -1, the maximum range is the beginning of a string
If you want to achieve access to the sub-section from a string, it may be used [superscript head: Tail index] to intercept the corresponding string, where the subscript 0 is counted from the beginning, can be positive or negative, the represent landmarks may take empty head or tail.
[The header: Tail index] substring of characters acquired target comprising the head, but not the end of the target character.
The following example:
str = 'Hello World!'
Print STR [ 2 : . 5 ] String # output string between the third to sixth
4.Python list
List with [] identified python is the most common complex data type.
And a list of strings can also be taken as
Cutting the value list may be used in variable [head index: Tail index], the corresponding list will be taken, beginning from left to right index 0 by default, default indexes from right to left at -1, the subscript may be empty means taking the head or tail.
Plus + is the concatenation operator list, the asterisk * is repeated.
5.Python tuple
Tuple is another data type, similar List (list).
A tuple identifier (). Internal element separated by commas. But not the second tuple assignment, equivalent to the read-only list.
6.Python dictionary
Dictionary (dictionary) python is in addition to being outside the list of the most flexible type of built-in data structures. List is an ordered collection of objects, dictionaries are unordered collections of objects.
The difference between the two is that: among the elements of the dictionary is by the access key , rather than by shifting access.
Dictionaries with "{}" logo. A dictionary index (key) value and a value corresponding to its composition.
如 dict = {'name': 'john','code':6734, 'dept': 'sales'}
7. Data type conversion
Data types will involve the issue of some data type conversion
