連想配列

連想配列にはassocを使う。

gosh> (assoc "b" '(("a" 1) ("b" 2)))
("b" 2)
gosh> (assoc "c" '(("a" 1) ("b" 2)))
#f
gosh> (cadr (or (assoc "b" '(("a" 1) ("b" 2))) '("" "")))
2
gosh> (cadr (or (assoc "c" '(("a" 1) ("b" 2))) '("" "")))
""

cadrでエラーが出てしまうのを or で防いでいるのがいまいち。

gosh> (let ((x (assoc "a" '(("a" 1) ("b" 2))))) (if x (cadr x) ""))
1
gosh> (let ((x (assoc "c" '(("a" 1) ("b" 2))))) (if x (cadr x) ""))
""

こうかな。
取りあえず関数化していみないｗ

gosh> ((lambda (x) (let ((x (assoc x '(("a" 1) ("b" 2))))) (if x (cadr x) ""))) "a")
1
gosh> ((lambda (x) (let ((x (assoc x '(("a" 1) ("b" 2))))) (if x (cadr x) ""))) "b")
2
gosh> ((lambda (x) (let ((x (assoc x '(("a" 1) ("b" 2))))) (if x (cadr x) ""))) "c")
""