수업에서 알려주신 코드로 실행을 하면 잘 실행이 되는데

변수를 만들지 않고 코드를 작성해보니 에러가 납니다.

어떤 부분이 잘못된 걸까요?

작성한 코드 및 에러 메세지

문제에서 제시된 코드

let mise_list = [ { MSRDT: "201912052100", MSRRGN_NM: "도심권", MSRSTE_NM: "중구", PM10: 22, PM25: 14, O3: 0.018, NO2: 0.015, CO: 0.4, SO2: 0.002, IDEX_NM: "좋음", IDEX_MVL: 31, ARPLT_MAIN: "O3", }, { MSRDT: "201912052100", MSRRGN_NM: "도심권", MSRSTE_NM: "종로구", PM10: 24, PM25: 18, O3: 0.013, NO2: 0.016, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 39, ARPLT_MAIN: "PM25", }, { MSRDT: "201912052100", MSRRGN_NM: "도심권", MSRSTE_NM: "용산구", PM10: 0, PM25: 15, O3: 0.012, NO2: 0.027, CO: 0.4, SO2: 0.003, IDEX_NM: "점검중", IDEX_MVL: -99, ARPLT_MAIN: "점검중", }, { MSRDT: "201912052100", MSRRGN_NM: "서북권", MSRSTE_NM: "은평구", PM10: 36, PM25: 14, O3: 0.019, NO2: 0.018, CO: 0.5, SO2: 0.005, IDEX_NM: "좋음", IDEX_MVL: 42, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "서북권", MSRSTE_NM: "서대문구", PM10: 28, PM25: 9, O3: 0.018, NO2: 0.015, CO: 0.6, SO2: 0.004, IDEX_NM: "좋음", IDEX_MVL: 37, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "서북권", MSRSTE_NM: "마포구", PM10: 26, PM25: 8, O3: 0.012, NO2: 0.021, CO: 0.5, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 36, ARPLT_MAIN: "NO2", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "광진구", PM10: 17, PM25: 9, O3: 0.018, NO2: 0.016, CO: 0.6, SO2: 0.001, IDEX_NM: "좋음", IDEX_MVL: 31, ARPLT_MAIN: "O3", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "성동구", PM10: 21, PM25: 12, O3: 0.018, NO2: 0.017, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 33, ARPLT_MAIN: "PM25", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "중랑구", PM10: 27, PM25: 10, O3: 0.015, NO2: 0.019, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 34, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "동대문구", PM10: 26, PM25: 9, O3: 0.016, NO2: 0.017, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 34, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "성북구", PM10: 27, PM25: 8, O3: 0.022, NO2: 0.014, CO: 0.5, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 37, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "도봉구", PM10: 25, PM25: 12, O3: 0.024, NO2: 0.011, CO: 0.3, SO2: 0.002, IDEX_NM: "좋음", IDEX_MVL: 41, ARPLT_MAIN: "O3", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "강북구", PM10: 30, PM25: 15, O3: 0.022, NO2: 0.02, CO: 0.4, SO2: 0.002, IDEX_NM: "좋음", IDEX_MVL: 39, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "동북권", MSRSTE_NM: "노원구", PM10: 21, PM25: 14, O3: 0.017, NO2: 0.016, CO: 0.4, SO2: 0.004, IDEX_NM: "좋음", IDEX_MVL: 36, ARPLT_MAIN: "PM25", }, { MSRDT: "201912052100", MSRRGN_NM: "서남권", MSRSTE_NM: "강서구", PM10: 36, PM25: 16, O3: 0.021, NO2: 0.013, CO: 0.4, SO2: 0.004, IDEX_NM: "좋음", IDEX_MVL: 42, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "서남권", MSRSTE_NM: "구로구", PM10: 23, PM25: 10, O3: 0.022, NO2: 0.016, CO: 0.3, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 37, ARPLT_MAIN: "O3", }, { MSRDT: "201912052100", MSRRGN_NM: "서남권", MSRSTE_NM: "영등포구", PM10: 29, PM25: 15, O3: 0.01, NO2: 0.022, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 41, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "서남권", MSRSTE_NM: "동작구", PM10: 29, PM25: 15, O3: 0.012, NO2: 0.023, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 41, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "서남권", MSRSTE_NM: "관악구", PM10: 27, PM25: 12, O3: 0.012, NO2: 0.022, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 37, ARPLT_MAIN: "NO2", }, { MSRDT: "201912052100", MSRRGN_NM: "서남권", MSRSTE_NM: "금천구", PM10: 25, PM25: 15, O3: 0.015, NO2: 0.02, CO: 0.4, SO2: 0.004, IDEX_NM: "좋음", IDEX_MVL: 43, ARPLT_MAIN: "PM25", }, { MSRDT: "201912052100", MSRRGN_NM: "서남권", MSRSTE_NM: "양천구", PM10: 0, PM25: 14, O3: 0.016, NO2: 0.017, CO: 0.4, SO2: 0.003, IDEX_NM: "점검중", IDEX_MVL: -99, ARPLT_MAIN: "점검중", }, { MSRDT: "201912052100", MSRRGN_NM: "동남권", MSRSTE_NM: "강남구", PM10: 31, PM25: 16, O3: 0.018, NO2: 0.018, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 39, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "동남권", MSRSTE_NM: "서초구", PM10: 34, PM25: 13, O3: 0.024, NO2: 0.019, CO: 0.3, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 41, ARPLT_MAIN: "PM10", }, { MSRDT: "201912052100", MSRRGN_NM: "동남권", MSRSTE_NM: "송파구", PM10: 25, PM25: 6, O3: 0.014, NO2: 0.025, CO: 0.4, SO2: 0.003, IDEX_NM: "좋음", IDEX_MVL: 42, ARPLT_MAIN: "NO2", }, { MSRDT: "201912052100", MSRRGN_NM: "동남권", MSRSTE_NM: "강동구", PM10: 24, PM25: 14, O3: 0.016, NO2: 0.02, CO: 0.4, SO2: 0.002, IDEX_NM: "좋음", IDEX_MVL: 39, ARPLT_MAIN: "PM25", }, ];

여기서 미세먼지가 40보다 작은 구의 이름을 찾는 문제를 해결하려고 함.

수업에서 나온 코드

for(let i=0; i<mise_list.length; i++){
 let mise=mise_list[i]; 
  if (mise["IDEX_MVL"]<40){
   let gu_name=mise["MSRSTE_NM"]; 
   let gu_mise=mise["IDEX_MVL"]; 
   console.log("40보다 작은 구 :" + gu_name + "," + gu_mise);
       }
       }

변수를 사용하지 않고 코드를 작성해보려고 했는데 에러..

for(let i=0; i<mise_list.length; i++){
   if(mise_list[i]["IDEX_MVL"]<40){
  console.log(mise_list[i]["MSRSTE_NM"]
    } 
}