Don't display duplicate column data from Matrix

Question

If I have a matrix field with data like

Mon    X    Y
Mon    A    B
Tue    X    Y
Wed    X    Y
Wed    A    B

how can I output that on the front-end so that it looks like

Mon    Tue    Wed    
X Y    X Y    X Y
A B           A B

At the moment I'm getting

Mon    Mon    Tue    Wed    Wed    
X Y    A B    X Y    X Y    A B

Answer 1

Sounds like a good use for stash. Capture the matrix (or the entire entry, it's up to you). The following assumes you know how to capure and set a list with stash, ie:

{exp:stash:set_list name="matrix_block"}         
<!-- Capture the matrix to a list -->
    {matrix_field}
        {stash:day}{day}{/stash:day} <!-- The day -->
        {stash:col_1}{event_1}{/stash:col_1} <!-- Value 1 -->
        {stash:col_2}{event_2}{/stash:col_2}
    {/matrix_field}
{/exp:stash:set_list}




<!-- Now we have a list, duplicate it and create new list using only the days -->
{exp:stash:split_list 
    name="daysofweek"
    list="matrix_block"
    match="#[a-zA-Z]#"
    against="day"
}

<!-- Now out put the sucker -->
{exp:stash:parse} <!-- Make sure everything else is set before trying to target data -->

{exp:stash:get_list name="daysofweek" unique="day" require_prefix="yes" prefix="out" } <!-- 
    Get the days from our duplicated list, using unique="" makes sure we dont get duplicate days,
    force prefix so inner get_list doesn't bork -->

    <li>{out:day} <!-- The unique day -->

        {exp:stash:get_list:sub name="matrix_block" match="#^{out:day}$#" against="day" parse="inward" }<!--
            Get the full list, match the contents 'day' against the day in this list -->

            <ul>
                <li>{col_1} {col_2}</li>
            </ul>
        {/exp:stash:get_list:sub}

    </li>

{/exp:stash:get_list}
{/exp:stash:parse}

Mae sure your Stash is up-to-date. Tested locally with hard coded list and works fine.

Update: stash:get_list:sub is used when you're inside a get_list already. I used sub but could be elephant.

'raw' refers to the initial set_list name, updated code I mistakenly used raw instead of matrix_block