List of Python3

List usage (lists)

1.list function can cut the string into List

In [2]: arr = list (' python ') in [3]: arrout[3]: [' P ', ' y ', ' t ', ' h ', ' o ', ' n ']

2. traversing the list

In [7]: For i in [' A ', ' B ', ' C ']: ...: print (i) ...: ABC

3. length, maximum value, minimum value

in []: arr = [1,3,5,-2,-8,357]in]: print (len) 6In [+]: print (max (arr)) 357In []: Print (arr)-8

4.del Delete an element from the list

in [+]: arrout[17]: [1, 3, 5,-2,-8, 357]in []: arr = [' C + + ', ' C ', ' Java ', ' HTML ']in []: Del arr[2]in []: Print (arr) [ ' C + + ', ' C ', ' HTML ']

5.list can do multiplication

In [8]: arr = [' js ', ' python ', ' css ', ' HTML ']in [9]: arr * 2out[9]: [' js ', ' python ', ' css ', ' html ', ' js ', ' python ', ' css ', ' H Tml ']in []: arr1 = [' mon ', ' tus ']in [all]: Arr + arr1out[11]: [' js ', ' python ', ' css ', ' html ', ' mon ', ' tus '

6. modifying values and slices

in [+]: arr= [' C ', ' Python ', ' css ', ' JS ', ' HTML ', ' node ']in []: arr[0]out[22]: ' C ' in [All]: arr[-1]out[23]: ' node ' in [+]: A RR[1] out[24]: ' Python ' in [+]: arr[-3]out[25]: ' JS '

7. Slice---Get a portion of the continuous data in the list

>>>arr= [' C ', ' Python ', ' css ', ' JS ', ' HTML ', ' node ']>>>print arr[1:3][' python ', ' CSS '] >>>print arr[0:1][' C ']>>>print arr[-1:-3][]>>>print arr[-3:-1][' JS ', ' HTML ']in [26]: arr= [' C ', ' Python ', ' css ', ' JS ', ' HTML ', ' node ']in [27]: print (Arr[1:3]) [ ' Python ',  ' css ']in [28]: print (arr[0:1]) [' C ']in [29]: print (arr[-1:-4]) []in [30] :  print (arr[-1:-3]) []in [31]: print (Arr[-3:-1]) [' JS ',  ' HTML ']in [32]: print (arr[ 3:])    [' JS ',  ' HTML ',  ' node ']in [33]: print (arr[::]) [' C ',  ' Python ',   ' CSS ',  ' js ',  ' HTML ',  ' node ']in [34]: print (Arr[:3]) [' C ',  ' python ',  ' CSS ']>>>print arr[-3:]  [' js ', ' HTML ',  ' node ']>>>print arr[3:]  [' JS ', ' HTML ',  ' node ']>>>print arr[:3][' C ', ' Python ',  ' CSS ']>>>print arr[: ] [' C ', ' PYTHon ',  ' css ',  ' js ',  ' HTML ',  ' node ' 

8. Slices can be assigned values

in [+]: arrout[35]: [' C ', ' Python ', ' css ', ' JS ', ' HTML ', ' node ']in [approx]: arr[2:4]=[' pc ', ' WD '] in [PNS]: arrout[37]: [' C ', ' Python ', ' pc ', ' WD ', ' HTML ', ' node '

9. The function of slicing can be inserted into and delete elements

In [St]: arrout[39]: [' C ', ' Python ', ' pc ', ' WD ', ' HTML ', ' node ']in [+]: arr[1:1]= [' pc ', ' wd ']in [+]: arrout[41]: [' C ', ' PC ', ' wd ', ' python ', ' pc ', ' WD ', ' HTML ', ' node ']in []: arr[2:3]= [] in [+]: arrout[43]: [' C ', ' pc ', ' Python ', ' pc ', ' WD ', ' HTML ', ' node '

10.append appends the last element to the list

In []: arr= [' wd ', ' Woniu ', ' LP ']in ["]: Arr.append (' Suiji ') in []: arrout[46]: [' wd ', ' Woniu ', ' LP ', ' Suiji ']

11.count statistics The number of occurrences of an element in the list

In [a]: arr= [2,3,4,5,6,7,8,9,43,24,234,423,423,12,2,3,4,52,2]in]: Arr.count (2) out[48]: 3

12. Bubble sort

In [the]: arr= [1,2,3,123,11,123,421,124,2,3,4,5,6]in]: For I in range (len (arr)-1): ....: For L in range (len)- 1-i): .....: If arr[l]>arr[l+1]: ....: Arr[l],arr[l+1]=arr[l+1],arr[l] ....: in [5 1]: arrout[51]: [1, 2, 2, 3, 3, 4, 5, 6, 11, 123, 123, 124, 421]

13.extend extension Source list (modified original list, no return value)

in [+]: b = [7,8,9,2]in]: a = [1,2,3]in]: b = [4,5,6]in []: A.extend (b) in [The]: B.extend (a) in []: aout[58]: [ 1, 2, 3, 4, 5, 6]in [bout[59]: [4, 5, 6, 1, 2, 3, 4, 5, 6]

14.index find a value from the list and return the index position of the first occurrence

in [+]: arr= [2, ' B ', 3, ' C ', 2,4,7]in [max]: Arr.index (' B ') out[61]: 1In [+]: Arr.index (' C ') out[62]: 3

15.insert Queue Arr.insert (position, inserted content) suddenly came a beautiful woman, to jump the queue, we are embarrassed to refuse

in [+]: arr= [1,2,3,4,5,6,7]in]: Arr.insert (3, ' four ') in [all]: arrout[65]: [1, 2, 3, ' Four ', 4, 5, 6, 7]

16.pop removes the elements from the list according to the index, and returns, by default deleting the last one (without passing arguments, and append, the only way pop is the only one that modifies the source list and returns the value)

In [4In]: arr= [1,2,3,4]in]: Arr.pop () out[67]: [[]: arrout[68]: [1, 2, 3]in []: arr= [1,2,3,4]in]: Arr.pop (2 ) out[70]: 3In [[]: arrout[71]: [1, 2, 4]

17.remove Delete elements based on values, delete first match (if no match, error)

In [the]: arr= [' A ', ' B ', ' C ', ' d ']in []: Arr.remove (' a ') in []: arrout[76]: [' B ', ' C ', ' d ']# Remove if there is no match to the exception that is thrown in [ValueError]: Arr.remove (' asdf ')-----------------------------------valueerror: List.remove (x): X not in List

18.reverse List Reverse-modify lists, do not return a value

In [the]: arr= [1,2,3,4]in]: Arr.reverse () in []: arrout[80]: [4, 3, 2, 1]

19.sort methods for sorting, modifying the list itself

In [Bayi]: arr= [ -11,2,1,5]in]: Arr.sort () in []: arrout[83]: [-11, 1, 2, 5]

Some methods of Dict

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List of Python3