python tuple

tuple

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Python's tuple is similar to a list, except that the elements of the tuple cannot be modified . The tuple uses parentheses, and the list uses square brackets. After the tuple is declared, the length is fixed.

In [1]: my_strs=("a","bbb",'ccc')

In [2]: my_strs
Out[2]: ('a', 'bbb', 'ccc')

In [3]: my_strs[0]
Out[3]: 'a'

In [4]: my_strs[-1]
Out[4]: 'ccc'

In [5]: my_strs[3]
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-5-978c5894f0f0> in <module>()
----> 1 my_strs[3]

IndexError: tuple index out of range

In [6]: my_strs[0]="aaa"
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-6-4152d9453e33> in <module>()
----> 1 my_strs[0]="aaa"

TypeError: 'tuple' object does not support item assignment

In [ 8]: len(my_strs) #The tuple is   defined , and the length is fixed. 
Out[8]: 3


In [11]: name=[1,2,3,4]

In [ 12]: my_tuple=(100,200,name) #The elements in the tuple are lists 

In [ 13 ]: my_tuple
Out[13]: (100, 200, [1, 2, 3, 4])

In [15]: my_tuple[2]
Out[15]: [1, 2, 3, 4]

In [ 16]: my_tuple[2][0]=100 #If the tuple contains a list, the list itself can be modified. 

In [ 17 ]: my_tuple
Out[17]: (100, 200, [100, 2, 3, 4])

Tuples are not added, deleted, or modified, only the built-in functions index, count, in, not in are searched.

In [17]: my_tuple
Out[17]: (100, 200, [100, 2, 3, 4])

In [19]: my_tuple.index(100)
Out[19]: 0

In [20]: my_tuple.count(100)
Out[20]: 1

In [21]: 100 in my_tuple
Out[21]: True

In [22]: 100 not in my_tuple
Out[22]: False

In [23]: