不区分大小写的字符串过滤器

Question

This is a line of code I found :

if(!word.matches("[a-zA-Z]{"+word.length()+"}")) return;

Specifically what does {"+word.length()+"} do, what's the logic behind it, and where can I read more about it?

Answer 1

Curly braces here mean that number of symbols, for example {4} means exactly four symbols. Here you specify entire string (inserting the length of it) to consist of small or large latin letters. Also you can specify {2-4} for example, meaning interval of number of letters that match given pattern. Hope this helps.

Answer 2

You are misreading the parameters... this:

"[a-zA-Z]{"+word.length()+"}"

is the same as

    "[a-zA-Z]{" // this is a string

+

    word.length() // this is getting an integer( is the length of the string word)

+

    "}" //another litt. string.

so you are technically concatenating 2 strings and putting in the middle a number...

just that