18.06.27

[Python] 3항 연산자

ret = 1 if (condition) else 2

[Js] setTimeout, setInterval, clearInterval

setTimeout(fn, dealy) // delay 후 fn 실행
setInterval(fn, interval) // interval 마다 fn 실행
clearInteval(repeat) // 반복을 멈춤

var cnt = 0;
var repeat = setInterval(function(){
    console.log(cnt++);
    if(cnt == 5)
        clearInterval(repeat);
}, 1000)

[Python] 파일 읽기

f = open("C:/doit/새파일.txt", 'r')
lines = f.readlines()
for line in lines:
    print(line)
f.close()

[MySQL] Covering Index

# 1
select *
from usertest
where chgdate like '2010%'
limit 100000, 100
# 2

from (
      select userno
      from usertest
      where chgdate like '2012%'
      limit 100000, 100
) b join usertest a on b.userno = a.userno