TypeError: Cannot read property **** of undefined？

TypeError: Cannot read property **** of undefined？TypeError: Cannot read property **** of undefined？

 getList() {    wx.cloud.callFunction({      name: "getwz",      complete: res => {        for (let i = 0; i < res.result.data.length; i++) {          res.result.data[i].wzzt = res.result.data[i].sj[this.data.sjxxindex][0]          this.setData({            rmb: res.result.data          })        }      }    })错误信息： TypeError: Cannot read property 'undefined' of undefined

 getList() {    wx.cloud.callFunction({      name: "getwz",      complete: res => {        for (let i = 0; i < res.result.data.length; i++) {          res.result.data[i].wzzt = res.result.data[i].sj[this.data.sjxxindex][0]          this.setData({            rmb: res.result.data          })        }      }    })错误信息： TypeError: Cannot read property 'undefined' of undefined

回答：