我的问题是,我想将列表中的每个小写字母更改["hello","wHatS", "up?"]为大写字母.
["hello","wHatS", "up?"]
map toUpper [x] 不起作用...
map toUpper [x]
它应该返回["HELLO","WHATS","UP？"] ..
string haskell list
haskell ×1
list ×1
string ×1