value expression in charts

[fleur]

Hello,

I want to make a chart with all columns of my table in the x axis (category expression) and their value in y axis (value expression). The problem is that their values in the y axis are not numeric, they are carachters( '-', '=' , '+'  or  '++' )

 I did a substitution of my characters into integers, but now i want my charachters to appear not integers, didn't know how to do that

Anyone has an idea please?

thanks