"Turn" Python Learning (8) tuples

Transfer from http://www.cnblogs.com/BeginMan/p/3156235.html

One, tuple characteristics

1, similar list, but immutable type, because of this, it can do a dictionary key
2, when processing a group of objects, this group by default is a tuple type (old write wrong "Yuan zu")
3, all the multi-object, comma-delimited, not explicitly defined by the symbol of these are the tuple type by default

1 >>>‘Abc', 1, 2,‘X‘, True2 (‘Abc', 1, 2,‘X‘, True)3 >>> x, y =1,24 >>>X, y 5 (1, 2)  6---------------- ------------- 7 def Foo1 () :  8 return obj1,obj2,obj3< Span style= "COLOR: #008080" > 9 10 11 def Foo2 (): 12  Return [Obj1,obj2,obj3]13 14 def Foo3 (): 15 return (obj1,obj2,obj3)       

4 , comma not less, try to write, even if there is only one element

>>> Type (‘X‘)) <type‘Str' >>>> type (( "x"  ,)) <type  ' tuple "> >>> tup = ( ' x " Span style= "COLOR: #000000" >) >>> type (TUP) <type  "str" >>>> Tup = ( ' x ") >>> type (tup) <type  tuple ";        

Feel good: hi.baidu.com/wuxinzy/item/c2c3cd428c99aa01896d10a7

1. Unable to add elements to the tuple. Tuples do not have a append () or extend () method.
2. You cannot delete an element from a tuple. The tuple does not have a remove () or pop () method.
3. You can find an element in a tuple, because the operation does not change the tuple.
4. You can also use the In operator to check if an element exists in a tuple. So what good is a tuple?

? Tuples are faster than lists. If you define a series of constant values, and all you need to do is traverse it, use a tuple substitution list.
? "Write protection" of data that does not need to be changed will make the code more secure. Using a tuple substitution list is like having an implied assert statement that shows that the data is
? Some tuples can be used as dictionary keys (especially tuples that contain immutable data such as strings, numeric values, and other tuples). The list can never be used as a dictionary key because the list is not immutable.

"Turn" Python Learning (8) tuples