If elif else condition to insert new data into the existing column

How to use the if elif else condition to insert the data into the existing column?

Example, if the columnA = 'abc' then columnB return '123', if the columnA = 'efg' then columnB return '345', else return '0'.

so based on the data it should be:

if the Sale id = 'sale001' then Sale no return 'clo sale', elif the Sale id = 'sale002' then Sale no return 'blo sale', else return ''.

enter image description here

Hello @beginof,

I think you’ve got the gist of it.

Instead of thinking about it being a table, think of it as a dataframe that you are manipulating and then return the resulting dataframe to a table.

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HI @jinnyzor,

Yes, initially I also think about this concept. But how if the value that i need to put as a link or button which able to connect to another page and so on?

To allow for inserting links into a datatable, you can use a markdown column.

You can do this by passing presentation: markdown for those specific columns. And then in your data, you can create the links via markdown:

HI @jinnyzor,

Can you share some sample code?

Actually, I had a dash_table.DataTable require to insert the additional value which is a link or button that can connect to another page of the multi-page dashboard.

Can you give me the structure of the target link?

some kind like this.


When I add the def info2(row) into the def update_table(selection) in order to insert the data for the ‘Sale no’ column, it will show error:

Invalid argument data[7].refer passed into DataTable with ID “tabletrn”.
Expected one of type [string, number, boolean].

            html.P("Transaction status detail:",
                                        {'name': 'Product', "id": 'product'},
                                        {'name': 'Sale id', "id": 'info'},
                                        {'name': 'Amount', "id": 'amount'},
                                        {'name': 'Sale no', "id": 'refer'},

                                style_cell={'textAlign': 'left'},


    Output('tabletrn', 'data'), 
    Input('trnid_dd', 'value')

def update_table(selection):
    if len (selection) == 0:
        return dash.no_update
        dff = df[df['Sale id'] == selection]  

        transpose = dff.melt(id_vars = ['Product' ,'Amount']
                  ,var_name = ['header']
                  ,value_name = 'info')

        def info2(row):
            if row['header'] == 'sale001':
                return 'clo sale'
            elif row['header'] == 'sale002':
                return 'blo sale'
            # else:
            return ''
        info['refer'] = info.apply (lambda row: info2(row), axis=1)
        info3 = info.copy()
        columns = info3[['header','info', 'refer']]

        data= columns.to_dict('records')

        return data

Any idea?

What columns does this other table have? My guess is that it doesn’t have this column of refer.

sorry, i put in wrong information.

already amended.

Before the return, print the columns.

What does it show?

Unable to print in the table callback
but I had try to print it without the callback, the result is exactly what I expect,
there is not issue if print in dataframe
therefore, I only move the solution into the table callback
but when move in, the error came out in the table callback

Can you show snippet of what the df looks like before you try to return it?

like the first image i show


I saw there is no issue in dataframe when I print it to the .csv, then I only apply the same method to my data table.
But error came out.

Without the second def, there is no issue for the data table.

The second def I m using to add in the additional information for specified row data into the new column.

Instead of doing that function, just make it a straight if then statement.

            if row['header'] == 'sale001':
                info[‘refer’] =  'clo sale'
            elif row['header'] == 'sale002':
                info[‘refer’] = 'blo sale'
                info[‘refer’] = ‘’

I had tried this solution last time, but it will show error

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().