Question

我有一个50000 * 2的单元格，其中包含数字内容。现在我想替换第二列，其数字范围从1到10，对应的字符串如'airplane'表示1，'automobile'表示2，依此类推。什么是最有效的方法？我首先尝试将第二列内容拆分为新的单元格class1并将其转换为字符串并尝试通过应用以下代码进行替换：

classes1(strcmp('1',classes1))={'airplane'};
classes1(strcmp('2',classes1))={'automobile'};
classes1(strcmp('3',classes1))={'bird'};
classes1(strcmp('4',classes1))={'cat'};
classes1(strcmp('5',classes1))={'deer'};
classes1(strcmp('6',classes1))={'dog'};
classes1(strcmp('7',classes1))={'frog'};
classes1(strcmp('8',classes1))={'horse'};
classes1(strcmp('9',classes1))={'ship'};
classes1(strcmp('10',classes1))={'truck'};

但那并不成功。它只用'卡车'代替'10'。

更新：此代码实际上有效。但在我的情况下，必须使用字符串'1'而不是'1'（缺少空格）。

Answer 1

使用此功能扩展到您的大案例 -

%%// Create look up and numeral data cell arrays for demo
LOOKUP_CELL_ARRAY = {'airplane','automobile','chopper'};
IN_CELL_ARRAY = num2cell(round(1+2.*rand(10,2)))

%%// Replace the second column of data cell array with corresponding
%%// strings in the look up array
IN_CELL_ARRAY(:,2)= LOOKUP_CELL_ARRAY(cell2mat(IN_CELL_ARRAY(:,2)))

输出 -

IN_CELL_ARRAY = 

    [2]    [2]
    [2]    [2]
    [2]    [1]
    [2]    [2]
    [3]    [1]
    [2]    [3]
    [1]    [1]
    [3]    [3]
    [2]    [2]
    [2]    [3]


IN_CELL_ARRAY = 

    [2]    'automobile'
    [2]    'automobile'
    [2]    'airplane'  
    [2]    'automobile'
    [3]    'airplane'  
    [2]    'chopper'   
    [1]    'airplane'  
    [3]    'chopper'   
    [2]    'automobile'
    [2]    'chopper'

Answer 2

您可以使用cellfun执行以下操作：

% replacement strings
R = {'airplane','automobile','bird','cat','deer', ...
     'dog','frog','horse','ship','truck'};

% example data
nums = randi(10,100,1);
data(:,1) = num2cell(nums)
data(:,2) = cellstr(num2str(nums))

data = 

    [ 3]    ' 3'
    [ 1]    ' 1'
    [ 1]    ' 1'
    [ 8]    ' 8'
    [ 8]    ' 8'
    [ 8]    ' 8'
    [ 7]    ' 7'
    [ 9]    ' 9'
    [ 1]    ' 1'
    ...

str2double(x)不关心其'01'或'1'：

% replicate number strings with strings
data(:,2) = cellfun(@(x) R( str2double(x) ), data(:,2) )


data = 

    [ 3]    'bird'      
    [ 1]    'airplane'  
    [ 1]    'airplane'  
    [ 8]    'horse'     
    [ 8]    'horse'     
    [ 8]    'horse'     
    [ 7]    'frog'      
    [ 9]    'ship'      
    [ 1]    'airplane'   
    ...

Answer 3

您只需使用索引编制即可：

data = {'aa' 1
        'bb' 3
        'cc' 2
        'dd' 6
        'ee' 1
        'ff' 5}; %// example data: two-col cell array, 2nd col is numbers
str = {'airplane','automobile','bird','cat','deer', ...
       'dog','frog','horse','ship','truck'}; %// replacement strings

data(:,2) = str(vertcat(data{:,2})); %// do the replacing

MATLAB：如何用相应的字符串替换单元格的单个列中的数字？

3 个答案: