Python's strongest King (7) -- tuple and pythontuple
1. sequence ):
Note: In fact, we have used sequences in the previous string list. The reason why we put them here is mainly to help you understand and remember them.
Python Data Access Model: direct access, sequence, and ing
- Non-container classes can be directly accessed, and all numeric types are classified as such.
- Sequence type refers to the sequential access of elements in the container from 0 to one or more elements at a time. Returns the string, list, And tuples to the secondary class.
- The difference between the ing type and the sequence type is that it uses different indexes and sequential numeric offsets. Its elements are stored unordered and accessed by unique keys. Dictionary is of this type.
2. Python tuples
The Python tuples are similar to the list, except that the elements of the tuples cannot be modified.
2.1 create tuples
The tuples use parentheses, And the list uses square brackets.
Creating tuples is simple. You only need to add elements in brackets and separate them with commas.
Example 1:
#! /Usr/bin/env python #-*-coding: UTF-8-*-# @ Time: 2016/9/11 20:54 # @ Author: wwyxtup1 = ("python", "java ", "c", "c ++") tup2 = ("demassiya", "no", "") tup3 = ("", "", "Children's robbery", "baby fish", "Elementary School Monk") print "tup1 is as follows:" for var1 in tup1: print var1print "tup2 is as follows:" for var2 in tup2: print var2print "tup3:" for var3 in tup3: print var3
Example 1 running result:
The tup1 is as follows: pythonjavacc ++ tup2 is as follows: what about demaxa nosi? tup3 is as follows: Withdrawal Ji chushou suo children robbery baby fish Primary School monk
2.2 create null tuples
When only one element is contained in a tuple, you must add a comma after the element.
Tuples are similar to strings. subscript indexes start from 0 and can be truncated or combined.
Example 2
#! /Usr/bin/env python #-*-coding: UTF-8-*-# @ Time: 2016/9/11 20:54 # @ Author: wwyxtup1 = () # create an empty tuples tup2 = ("",) # create a tuple print tup1print tup2 [0]
Example 2 running result:
() What about IOU?
Note: The element traversal in the tuples is traversed Based on the Traversal method of the sequence. If tup2 is printed directly in the preceding example, tup2 is returned in the memory.
2.3 access tuples
- Tuples can be accessed through for iteration, as shown in Example 1.
- The access to tuples can also be traversed through the sequence index, as shown in example 2.
2.4 modify tuples
Note: element values in tuples cannot be modified, but we can concatenate and combine them.
Example 3:
#! /Usr/bin/env python #-*-coding: UTF-8-*-# @ Time: 2016/9/11 20:54 # @ Author: wwyxtup1 = ("python", "java ", "c", "c ++") tup2 = ("demassiya", "no", "") tup3 = ("", "", "Children's robbery", "baby fish", "Elementary School Monk") tup4 = tup1 + tup2 + tup3print "tup4 is as follows:" for var1 in tup4: print var1
Example 3 running result
The tup4 is as follows: pythonjavacc ++ what about demaxa Nova? withdraw money from Ji chushou suo children's robbery baby fish Elementary School monk
2.5 Delete tuples
Note: The element values in the tuples cannot be deleted, but we can use the del statement to delete the entire tuples.
Example 4
Tup2 = ("demassia", "NOVA", "") tup3 = ("withdrawal Ji", "nursery Suo", "Children robbery", "baby fish ", "Elementary School Monk") print "tup2 is as follows:" for var1 in tup2: print var1del tup2print "the deleted tup2 is as follows: "print tup2 [2] del tup3 [2] # Delete the element whose index of tup3 is 2
Example 4 running result
Tup2 is as follows: Traceback (most recent call last): demassiya File "E:/python/hello/untitled3/tuple. py ", line 14, in <module> Nova print tup2 [2] What about IOU? NameError: name 'tup2' is not defined the deleted tup2 is as follows:
3. tuples Operator
Like a string, you can use the plus sign (+) and minus sign (*) to perform operations between tuples. This means they can combine and copy, and a new tuples will be generated after the operation.
Python expressions |
Result |
Description |
Len (1, 2, 3 )) |
3 |
Calculate the number of elements |
(1, 2, 3) + (4, 5, 6) |
(1, 2, 3, 4, 5, 6) |
Connection |
['Hi! '] * 4 |
['Hi! ', 'Hi! ', 'Hi! ', 'Hi! '] |
Copy |
3 in (1, 2, 3) |
True |
Whether the element exists |
For x in (1, 2, 3): print x, |
1 2 3 |
Iteration |
4. tuples index, truncation
Because tuples are also a sequence, we can access the elements at the specified position in the tuples, or intercept some elements in the index, as shown below:
Tuples:
L = ('spam', 'Spam', 'SPAM!')
Python expressions |
Result |
Description |
L [2] |
'Spam! ' |
Read the third element |
L [-2] |
'Spam' |
Reverse reading; reads the second to last element |
L [1:] |
('Spam', 'spam! ') |
Truncation Element |
5. No Delimiter is closed
Any unsigned objects are separated by commas (,). The default value is tuples,
Example 5
Print "withdrawal Ji", "nursery Suo", "Children robbery", "baby fish", "Elementary School Monk" print "Timo captain", 1, 2, 3, 4
Example 5 running result
Withdrawal Ji chushou suo children's robbery baby fish Elementary School monk Timo Captain 1 2 3 4
Note: Remember this article and try not to use it on your own.
6. built-in functions of tuples
Common built-in functions of Python tuples:
Serial number |
Method and description |
1 |
Cmp (tuple1, tuple2) Compares two tuples. |
2 |
Len (tuple) Calculates the number of tuples. |
3 |
Max (tuple) Returns the maximum value of elements in the tuples. |
4 |
Min (tuple) Returns the minimum value of the element in the tuples. |
5 |
Tuple (seq) Converts a list to a tuples. |
Example 6
#! /Usr/bin/env python #-*-coding: UTF-8-*-# @ Time: 2016/9/11 20:54 # @ Author: wwyx # tup1 = ("python", "java ", "c", "c ++") tup2 = ("demassiya", "no", "") tup3 = ("", "", "Children's robbery", "baby fish", "Elementary School Monk") var1 = cmp (tup2, tup3) print "comparison result of tup2 and tup3:", var1print "maximum value of tup2 :", max (tup2) print "minimum value of tup3:", min (tup3)
Example 6 running result:
Comparison results of tup2 and tup3:-1tup2's maximum value: the minimum value of Novus tup3: Children's robbery
Now, let's talk about the next dictionary. Come on !!