How to insert a value inside a particular array of object

i am useing vue(vuetify) v-data-table to show some data, its working fine, in the same time i am trying to show some data from another api, so i need to know how to push a items inside of a array of object

axiosThis.tableDataFinal[i].push(axiosThis.printsumget[i])

i am getting .push is not a function