is this format. Doesn"t an array subscript correspond to a value? how can it correspond to three values? the data on my side are spliced like this. There is no way of thinking below 
here is my splicing code
const Str = []
for (let j = 0; j < this.role_obj.length; jPP) {
for (let i = 0; i < this.postForm.permissionList.length; iPP) {
if (this.postForm.permissionList[i].match(this.role_obj[j])) {
Str.push(this.postForm.permissionList[i].replace(this.role_obj[j], this.role_obj[j] + ":"))
}
}
}
console.info(Str)
this.postForm.permissionList = []
for (let i = 0; i < Str.length; iPP) {
this.postForm.permissionList[i] = Str[i]
console.info(this.postForm.permissionList[i])
}