如何以有组织的方式将值范围与字符串进行比较？

Question

this is a simple question.

I have a string which I have split into an array of characters. I need to iterate through each character and check if it is the same as a relevant one that indicates certain behaviour. How can I do this without having a bunch of if/switch statements. Other than create a new method which I implement that accepts multiple arguments and compares all of them, not sure what I can do here.

Thanks.

edit: I am looking for a good implementation of a function that can do this or a java statement (ie if statement) that would make this process easier.

edit2: mistagged as c#, but I regularly use both languages so I don't mind an explanation in either one.

Some crappy code to illustrate a simple example of what I mean:

`if (charsArray[i] == "-")
    s.push(charsArray[i]);
if (charsArray[i] == "+")
    s.push(charsArray[i]);
if (charsArray[i] == "[")
    s.push(charsArray[i]);
if (charsArray[i] == "]")
    s.push(charsArray[i]);`

Note: I would use a for loop to iterate through each char after it is an array of characters.

Answer 1

EDIT: The change from C# to java occurred while I was creating this. As such, this may not work.

Simple question, semi-complicated answer.

You could create a Dictionary <char, object> where object is some other Type that will work for you. After that, in your iterating through the string, check if the Dictionary contains the key and then... well, you can sort it out from there. :)

A suggestion, you could use a delegate or one of it's child types ( Action , Predicate , or Func ). I can't be any more specific as you did not post any code...

Answer 2

If the behavior is not unique for each symbol, two pretty good solutions are a switch:

switch(charsArray[i]) {
    case '+': case '-': case '[': case ']':
        s.push(charsArray[i]);
}

And String contains (this might be what the comment suggestion is referring to):

if("+-[]".contains(String.valueOf(charsArray[i]))) {
    s.push(charsArray[i]);
}

If the behavior is unique, you might use the strategy pattern with a HashMap:

// where charMap is some HashMap<Character, SomeStrategy>
SomeStrategy strat = charMap.get(charArray[i]);
if(strat != null)
    strat.execute();

(Which I think is the Java way to do what @bubbinator is suggesting. I don't know C# but I guess Dictionary is a hash table.)

Answer 3

Remove all "uninteresting" characters from the string (by replacing them with a blank), then push all remaining chars.

It's just two lines:

for (char c : str.replaceAll("[^-+\\[\\]]", "").toCharArray())
    s.push(c);`