December 2017
Beginner
624 pages
15h 38m
Korean
Content preview from Head First Python, 개정판 : 스스로 질문하며 답을 찾는 파이썬 학습서(Python 3)
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객체
객체
객체
객체
키#1
키#2
키#3
키#4
딕셔너리
156 Chapter 3
in으로 확인
런타임 KeyError 해결하기
리스트처럼 딕셔너리에서도
in
연산자로 키가 존재하는지 확인할 수 있습니다. 키가
존재하는지 여부에 따라
in
연산자의 결과로 인터프리터는 참이나 거짓값을 반환합니다.
KeyError
에러 때문에 런타임에 딕셔너리를 사용하기 어려운 상황이므로
in
연산자를
이용해 이 문제를 해결합시다.
fruits
라는 딕셔너리를 만들고 존재하지 않는 키 값에 접근할 때
in
을 이용해
KeyError
를
회피하는 기법을 적용해보겠습니다. 먼저 빈 딕셔너리를 만든 다음
apples
키에 대응하는 값
10
을 키/값 쌍으로 할당합니다. 딕셔너리의 행 데이터를 찾을 때
in
연산자를 이용해
apples
키가 현재 존재하는지 확인할 수 있습니다.
>>> fruits = {}
>>> fruits
{}
>>> fruits['apples'] = 10
>>> fruits
{'apples': 10}
>>> 'apples' in fruits
True
예상한 그대로입니다. 값은 키와
연관되어 있습니다.
‘
in
’
연산자로
키가 존재하는지 먼저 확인하면
런타임 에러를 방지할 수 있습니다.
다른 동작을 시도하기 전에 우선 인터프리터가 위 코드를 실행한 다음 메모리에 저장된
fruits
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and much more.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.