Substitute for join/ outerjoin in cell array?

2016 9 6
2 个回答
回答已采纳
更新时间：2016 9 6
3 次查看（30 天）

0 个投票

It seems join and outerjoin only work for tables. Is there a substitute for cell arrays?

请先登录，再回答此问题。

 采纳的回答

Guillaume
Guillaume 2016-9-6

2 个投票

Well, you can always convert your cell arrays to a table with cell2table, do the join and convert back.
Otherwise, it's not particularly hard to implement using ismember:
%INPUTS:
%leftcell: first cell array
%rightcell: second cell array
%leftkeys: column indices for left key
%rightkeys: column indices for right key
%JOIN:
[common, rows] = ismember(leftcell(:, leftkeys), righcell(:, rightkeys), 'rows');
joinedcell = [leftcell(common, :), rightcell(rows, :)];
%OUTERJOIN:
[commonleft, rows] = ismember(leftcell(:, leftkeys), righcell(:, rightkeys), 'rows');
commonright = ismember(rightcell(:, leftkeys), leftcell(:, rightkeys), 'rows');
joinedcell = [leftcell(commonleft, :), rightcell(rows, :)];
joinedcell = [joinedcell; ... normal join
[cell(sum(~commonright), size(leftcell, 2)), rightcell(~commonright, :)]; ... add non matching rows from rightcell
[leftcell(~commonleft, :), cell(sum(~commonleft), size(righcell, 2))]]; ...add non matching rows from leftcell
I've not merged the left and right keys. It's not particularlty hard to do, and you could also select which columns to include in the join, but you should get the idea from the above.

更多回答（1 个）

KSSV
KSSV 2016-9-6

0 个投票

You can join them...
k{1} = 1 ;
k{2} = [2 3] ;
l{1} = [3,4];
l{2} = [5] ;
% join them
kl = [k l] ;

2 个评论
显示 无 隐藏 无

phlie
phlie 2016-9-6
Thank you. Am I missing something or is there no merging key in your answer? Join/ outerjoin allows me to join data based on a common value of data k and l, i.e., I can merge even if the data is not ordered the same way (or if the dimensions don't match).
Guillaume
Guillaume 2016-9-6
编辑：Guillaume 2016-9-6
@Siva,
The joins ( join, innerjoin, outerjoin) in question are special functions that are not simple concatenation.
The concept comes from relational databases.

请先登录，再进行评论。

类别

在 帮助中心 和 File Exchange 中查找有关 Tables 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by