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
160 Chapter 3
장수하는 setdefault
‘setdefault’ 메서드 사용하기
현재 버전의
vowels5
.
py
는 존재하지 않는 키에 접근하려 하면서 런타임 에러, 특히
KeyError
가 발생했던 사실을 기억하세요.
이 코드를
실행하면 에러가
발생합니다.
fruits
실험을 통해
setdefault
를 이용하면 불필요한 에러를 방지할 수 있다는
사실을 확인했습니다.
setdefault
는 키가 존재하지 않을 때는 필요한 초기화를
해주고, 그렇지 않을 때는 아무 동작도 하지 않고 키와 관련된 값을 바꾸지 않습니다.
vowels5
.
py
코드에서 키를 사용하기 전에
setdefault
를 호출하면 키가
존재하는지 여부와 관계없이
KeyError
가 더 이상 발생하지 않을 겁니다.
여러분의
IDLE
편집 창에서
vowels5
.
py
를 열고 첫 번째
for
루프를 다음처럼
바꾸세요. 즉,
setdefault
호출을 추가하세요. 그러고 나서 새로운 버전을
vowels6
.
py
라는 이름으로 저장하세요.
for letter in word:
if letter in vowels:
found.setdefault(letter, 0)
found[letter] += 1
‘
setdefault
’
를
이용해
‘
KeyErr
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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.