Detailed list and tuples in Python

Common operations: Index, Shard, add, multiply, check whether an element belongs to a member of a sequence, length, minimum, maximum

Example:

NUMBERS=[100,34,67]
Len (numbers) #返回值为3max (numbers) #返回值为100min (numbers) #返回值为34

List :

1. List function

>>>list (' Hello ') [' H ', ' e ', ' l ', ' l ', ' O ']

* You can use join (for example: ". Join (Somelist)) to convert a list of components into a string

2, the operation of the list

Element Assignment Value:

>>>x=[1,2,3]>>>x[1]=4>>>x[1,4,3]

To delete an element:

>>>x=[' abc ', ' Def ', ' Ghi ', ' JK ']>>>del x[2]>>>x[' abc ', ' Def ', ' JK ']

Shard Assignment:

>>>x=list (' Happy ') >>>name[' H ', ' a ', ' P ', ' P ', ' Y ']>>>x[1:]=list (' ello ') >>>x[' H ', ' e ', ' l ', ' l ', ' O ']

3. List method:

Append

>>>x=[1,2,3]>>>x.append (4) >>>x[1,2,3,4]

Count

>>>x=[1,2,3,1,3,5,5]>>>x.count (3) 2

Extend

>>>a=[1,1]>>>b=[2,3]>>>a.extend (b) >>>a[1,1,2,3]

Index

>>>x=[' A ', ' B ', ' C ']>>>x.index (' B ') 1

Insert Insertion Element

>>>x=[1,2,3]>>>x.insert (2, ' a ') >>>x[1,2, ' A ', 3]

Pop removes the list element (the last one by default)

>>> x=[1,2,3,4]>>> x.pop () 4>>> x.pop (1) 2>>> x[1, 3]

Remove removes the first occurrence of a value in the list

>>> x=[' my ', ' to ', ' was ', ' she ', ' to ']>>> x.remove (' to ') >>> x[' My ', ' was ', ' she ', ' to ']

Reverse to store elements in the list in reverse

>>> x=[1,2,3]>>> x.reverse () >>> x[3, 2, 1]

>>> x=[1,2,3]>>> List (reversed (x)) [3, 2, 1]>>> x[1, 2, 3]

Sort for sorting the list at the original location

>>> x=[4,6,2,1,7,8,3]>>> x.sort () >>> x[1, 2, 3, 4, 6, 7, 8]>>> x=[4,6,2,1,7,8,3]> >> y=sorted (x) >>> x[4, 6, 2, 1, 7, 8, 3]>>> y[1, 2, 3, 4, 6, 7, 8]>>> X=[3,2,1]>>&G T Y=x>>> y.sort () >>> x[1, 2, 3]>>> y[1, 2, 3]

  >>> sorted (' hello ')  [' E ', ' h ', ' l ', ' l ', ' O ']

Tuples : Non-changing sequences

>>> (1, 2, 3) >>> (1, 2, 3) >>> () #空元组 () >>> 1,syntaxerror:invalid syntax& Gt;>> 1, (1,) >>> 1, #元祖必须有逗号 (1,) >>> (40+2,) (42, 42, 42)

The tuple function transforms a sequence into a narimoto group

>>> tuple ([3,2,1]) (3, 2, 1) >>> tuple (' abc ') (' A ', ' B ', ' C ')

Reasons for the non-substitution of tuples

• Tuples can be used as keys in the map

• Tuples exist as return values for many of the built-in functions and methods