MATLAB——元胞数组

Posted 2020-10-10 箬笠蓑衣

一、

1、元胞数组的创建

>>  a={\'matlab\',20;ones(2,3),1:10}

a = 

    \'matlab\'        [         20]
    [2x3 double]    [1x10 double]>>  a={\'matlab\',20;ones(2,3),1:10}

>>  b=[{\'matlab\'},{20};{ones(2,3)},{1:10}]

b = 

    \'matlab\'        [         20]
    [2x3 double]    [1x10 double]

a和b是等价的

>>  c={10}
c = 
    [10]

>> c(2,2)={5}

c =

[10] []
[] [5]

>> c(1,2)={2}

c =

[10] [2]
[] [5]

clear all

a={\'matlab\',20;ones(2,3),1:10}
b=[{\'matlab\'},{20};{ones(2,3)},{1:10}]
c={10}
c(1,2)={2}
c(2,2)={5}
c(2,1)=3

赋值需用花括号，下标用小括号。

>> isequal(a,b)

ans =

     1

>> whos
  Name      Size            Bytes  Class      Attributes

  a         2x2               596  cell                 
  ans       1x1                 1  logical              
  b         2x2               596  cell                 
  c         2x2               480  cell        

>> d=cell(3,3)

d = 

    []    []    []
    []    []    []
    []    []    []

2、元胞数组访问

>> str=a(1,1)

str = 

    \'matlab\'

>> class(str)

ans =

cell

>> str=a{1,1}

str =

matlab


>> class(str)

ans =

char

>> a{2,2}

ans =

     1     2     3     4     5     6     7     8     9    10

>> a(2,2)

ans = 

    [1x10 double]

（）和{}有着本质的区别，大括号用于表示元胞的内容，小括号表示指定的元胞。

>> a(2,2)(2)
错误: ()-索引必须显示在索引表达式的最后。
 
>> a{2,2}(2)

ans =

     2

>> b=c{2:3,2:3}

b =

     5

>> b=c(2:3,2:3)

b = 

    [5]    [6]
    [8]    [9]

b相当于从c中获取了四个元胞，用a的例子更好理解

>> d=a(2,:)

d = 

    [2x3 double]    [1x10 double]

>> d=a(2,2)

d = 

    [1x10 double]

>> d=a{2,2}

d =

     1     2     3     4     5     6     7     8     9    10

3、元胞数组的删除和重塑

     要删除单元数组中的行或列，可以用冒号表示单元数组中的行或列，然后对其赋一个空矩阵即可。

>> a={20,\'matlab\';ones(2,3),1:3}

a = 

    [        20]    \'matlab\'    
    [2x3 double]    [1x3 double]

>> a{1,2}=[]

a =

[ 20] []
[2x3 double] [1x3 double]

>> a{1,1}=[]

a =

[] []
[2x3 double] [1x3 double]

>> a={20,\'matlab\';ones(2,3),1:3}

a = 

    [        20]    \'matlab\'    
    [2x3 double]    [1x3 double]

>> a(2)

ans = 

    [2x3 double]

>> a(3)

ans = 

    \'matlab\'

可以看出四个元胞数组的排序

>> a{4}=[]

a = 

    [        20]    \'matlab\'
    [2x3 double]          []

>> a(4)=[]

a = 

    [20]    [2x3 double]    \'matlab\'

删除一个之后的重新排序。