List list:
Usage: used to store a plurality of values
Definitions: definitions in [] brackets, a plurality of values separated by a comma, the value may be any type
Conversion Type: Whenever loop can be traversed for the data types can be passed list () is converted into a list of type, list () will be the same for each element traversing the data type contained in the for loop is then placed with the list >>> List ( ' wdad ' ) # result: [ 'W', 'D', 'A', 'D'] >>> List ([l, 2,3]) # results: [1, 2, 3] > List >> ({ " name " : " Jason " , " Age " : 18 is}) # results: [ 'name', 'Age'] >>> List ((l, 2,3)) # results: [1 , 2, 3] >>> List ({1,2,3,4}) # results: [1, 2, 3, 4]
Common Operation: # 1, the index can take positive and negative values :( can preferably also stored) USER_INFO = [ ' Egon ' , 18 is, [ ' Football ' , ' EAT ' , ' SLEEP ' ]] Print (USER_INFO [ 2 ] [0]) >>> Football # 2, index slice my_friends = [ ' Tony ' , ' Jason ' , ' Tom ' ,. 4 ] Print (my_friends [0:. 4: 2]) # third parameter represents step >>> [ 'tony', ' Tom ' ] # . 3, the length len (): Get a list of the number of elements my_friends = [ ' Tony ' , ' Jason ' , ' Tom ' ,. 4 ] len (my_friends) >>>. 4 # . 4, operation members and in in Not my_friends = [ ' Tony ' , ' Jason ' , ' Tom ' ,. 4 ] ' Tony ' in my_friends >>> True ' Egon 'in my_friends >>> False # . 5, loop # looping through the list which my_friends value for I in my_friends: Print (I) ' Tony ' ' Jack ' ' Jason ' . 4 built-in method: # 1, Add # the append (): Append end of the list value, a one-time only add value L1 = [ ' a ' , ' B ' , ' C ' ] l1.append ( ' D ' ) Print (L1) >>> [ 'a', ' B ' , ' C ' , ' D ' ] # INSERT (): the value is inserted by the inserting position specified by the index L1 = [ ' A ' , ' B ' , ' C ' ] l1.insert (0, " First " ) # 0 represents the index position by interpolation Print (L1) >>> [ ' First ' , ' A ' , ' B ' , ' C '] #extend (): adding a plurality of disposable elements in the end of the list L1 = [ ' A ' , ' B ' , ' C ' ] l1.extend ([ ' A ' , ' B ' , ' C ' ]) Print (L1) >>> [ ' A ' , ' B ' , ' C ' , ' A ' , ' B ' , ' C '] # 2, delete # 2.1 the Remove (): Removes the specified value, can only delete a no return value L = [11,22,33,22,44 ] RES = l.remove (22) # from left to right to find the first brackets need to remove elements Print (RES) >>> None # 2.2 POP () default start delete from the list the last element, and returns the value delete, delete elements can be specified by adding the index in brackets l = [11,22 , 33,22,44 ] RES = l.pop () Print (RES) >>> 44 is RES = l.pop (. 1 ) Print (RES) >>> 22 is # 2.3 del completely remove the l = [11,22, 33, 44 ] del L [2] # deleted index elemental Print (L) >>> [11,22,44 ] # 3, reverse () reverse the order of elements in the list L = [11,22,33,44 ] l.reverse () Print (L) >>> [44,33,22,11 ] # . 4, Sort () to the list ordering all the elements within # listing 4.1 ordering between the elements must be the same data type, not mix, otherwise an error L = [11,22,3,42,7,55 ] l.sort () Print (L) >>> [3, 7, 11, 22, 42, 55] # default in ascending order L = [11,22,3,42,7,55 ] l.sort (Reverse = True) # Reverse specifying whether sorting fall the default is False Print (L) >>> [55, 42 is, 22 is,. 11,. 7,. 3 ] # . 5, the sorted (): Python built-in function, to generate a new list sorting, the same original data # 6 , count (): the number of specified elements in the current list = L [11,22,3,42,7,55,11 ] Print (l.count (. 11 )) >>> 2 # . 7, index (): Get the current value of the index of the specified element, you can also specify the Look = L [11,22,3,42,7,55,11 ] Print (l.index (11,1,7 )) >>>. 6 # . 8, Clear (): Clear list data l = [11,22 , 3,42,7,55,11 ] l.clear () Print (L) >>> [] supplementary knowledge: # queue: FIFO L1 = [] l1.append ( . 1 ) l1.append ( 2 ) l1.append ( . 3 ) Print (L1) l1.pop (0) Print (L1) l1.pop (0) l1.pop (0) Print (L1) # Stack: after the advanced L1 = [] l1.append ( . 1 ) l1.append ( 2 ) l1.append ( . 3 ) Print ( L1) l1.pop () Print (L1) l1.pop () l1.pop () Print (L1)