Both numeric and non-numeric data have different ASCII codes, that will be the first difference. Second, numeric data are stored in float, double, and int variables while non-numeric data are stored in char. However, both can be stored in a String variable if and only if the desired data to be stored will not be used for computuation using mathematical operations such as addition.
To store a non-numeric data in an array, the array must first be declared as a String variable array while a numeric data can be stored in an array once the array which will store the numeric data is declared as an integer, double, or float variable.