959bf1dc3022058

http://nhiro.org.s3.amazonaws.com/3/3/334b0a7165fdbe16161f19a03def6f80.jpg https://gyazo.com/334b0a7165fdbe16161f19a03def6f80

(OCR text)

破壊的変更って?

> X= "abc"

=> "abc"

> X << "d"

=> "abcd"

> X

=> "abcd"