how to find out the index of a cell array that cell contains my substring?

10 次查看（过去 30 天）
Rui Zhang
Rui Zhang 2024-2-15
评论： Rui Zhang 2024-2-16
My question is:
myCellArray = {'John','Mike','foo'};
substring = 'Jo'
Since myCellArray{1} contains "Jo', I expected the index = 1.
How to use cellfun to find the index of the element(s) in the cell array?
  2 个评论
Rui Zhang
Rui Zhang 2024-2-15
If I don't use cell function, the following code should work:
myCellArray = {'John','Mike','foo'};
substring = 'Jo';
indexForMySubstring = zeros([1,numel(myCellArray)]);
kk = 1;
for ii =1: numel(myCellArray)
if contains(myCellArray{ii},substring)
indexForMySubstring(kk) = ii;
kk = kk+1;
end
end
if kk>1.5
indexForMySubstring = indexForMySubstring(1:kk-1);
else
indexForMySubstring = [];
end
This will return array of the indexes that contains 'Jo' in myCellArray
But this code runs too slow when it is used for a large application.
I am looking for a solution that runs faster than this like using cellfun.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Fangjun Jiang
Fangjun Jiang 2024-2-15
Ran in:
Do you have to use cellfun()?
myCellArray = {'John','Mike','foo'};
substring = 'Jo'
substring = 'Jo'
find(contains(myCellArray,substring))
ans = 1
  7 个评论
显示 5更早的评论
Voss
Voss 2024-2-15
Ran in:
myCellArray = {[],'John','','Mike','foo'};
substring = 'Jo';
% replace non-char entries with empty chars:
fixedCellArray = myCellArray;
fixedCellArray(~cellfun(@ischar,fixedCellArray)) = {''};
myIndex = find(contains(fixedCellArray,substring))
myIndex = 2

请先登录，再进行评论。

更多回答（1 个）

Aquatris
Aquatris 2024-2-15
编辑：Aquatris 2024-2-15
Ran in:
Using the @Fangjun Jiang example, how about
myCellArray = {'John','Mike','foo','Jonathan','Stuart','Martha','Jo'};
substring = 'Jo';
idx = find(cellfun(@(x) contains(x,substring),myCellArray,'UniformOutput',true))
idx = 1×3
1 4 7
myCellArray(idx)
ans = 1×3 cell array
{'John'} {'Jonathan'} {'Jo'}
  4 个评论
显示 2更早的评论
Aquatris
Aquatris 2024-2-15
编辑：Aquatris 2024-2-16
Ran in:
Not the cleaness solution but I think you are looking for something like this then:
myCellArray = {[] 'John','Mike',[],'foo','Johanna','Mark',[];...
0 10 11 20 30 40 50 60;...
1 12 13 22 60 70 80 20;...
2 14 15 18 40 20 10 20;...
3 15 20 25 30 40 50 60};
substring = 'Jo';
idx_empty = cellfun(@isempty,myCellArray(1,:)); % find empty cells in first row
myCellArray_Modified = myCellArray(1,:); % create replica of first row of myCellArray
myCellArray_Modified(idx_empty) = {-1}; % replace empty cells with -1 double
idx = find(cellfun(@(x) contains(string(x),substring),myCellArray_Modified(1,:),'UniformOutput',true));
idx % idx is the column numbers of interest
idx = 1×2
2 6
myCellArray(:,idx)
ans = 5×2 cell array
{'John'} {'Johanna'} {[ 10]} {[ 40]} {[ 12]} {[ 70]} {[ 14]} {[ 20]} {[ 15]} {[ 40]}

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 的更多信息

标签

产品


版本

R2017b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by