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Java - How to split (+ sign) on Strings so it could be read as a Variable/Int?

开发者 https://www.devze.com 2023-03-28 18:49 出处:网络
This question is rather difficult to confer, for simplistic sake: I am loading some Strings via XML (XStream).

This question is rather difficult to confer, for simplistic sake:

I am loading some Strings via XML (XStream).

for example, Your total count is +variable+ .

The outcome would be

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"Your total count is +variable+ ."

when it ideally should be

"Your total count is" + variable + "." aka "Your total count is 1."

The issue: (if you can't see it) it reads the variable as if it were a String.

I know I would need to split that String from where the plus sign starts and ends and then connect it to the String, for it to read as a variable, like the above. But how? I need this to be done so that the String before the variable and after it is split.

so:

"Your total count is 50, would you like a cookie?"

aka

"Your total count is " + variable + " , would you like a cookie?"

Thank you alot!


Okay, I agree it's very confusing. I've edited this post (read below). Well I am loading some Strings via XML this could be the same case if I were loading them via a .txt or a config file.

On the XML file, I lay it out like so:

<list>
    <dialogue>
    <line>
    <string> Your total count is + Somewhere.totalCount +, Would you like a cookie?</string>
</line>
    </dialogue>
</list>

As you can see, the XML file can't locate where the variable (in a class is), nor can it recognise if it is a variable or a string.

I know that I would need to alter the way it reads it, so if there is a plus sign (+) anywhere on the String, it would simply "split" it away from the original String so I can reconnect it.

E.g. Your phone number is + PhoneBook.phoneNumber + should I call you? as it would be read from a XML file.

I want to "split" the String from front to back like so:

"Your phone number is " + PhoneBook.phoneNumber + " should I call you?" At the same time, I'm not assigning a variable because It's already declared in the XML file, I want it to recognise it as a int.


First, Java can not know that the +variable+ part of your string should be replaced with the value of the corresponding variable and also does not provide some "eval" like functionality like PHP or other scripting languages do, which might help you with that.

If you want to exactly replace this specific '+variable+' part of the string, it can be done like this:

int variable = 1;

String text = "Your total count is +variable+.";
String textWithVariableValue = text.replaceAll("\\+variable\\+", Integer.toString(variable));

But if you want to replace variables with arbitrary names, you will have to put them into a Map first, and then find all occurences of +somename+ in the string and replace it with the corresponding value stored in the map. Something like this:

Map<String, Object> variables = new HashMap<String, Object>();
variables.put("var1", 1);
variables.put("foo", 5);

String text = "var1 = +var1+, foo = +foo+";
String textWithVariableValues = text;
for (String variableName : variables.keySet()) {
    Object variableValue = variables.get(variableName);
    textWithVariableValues = textWithVariableValues.replaceAll("\\+" + variableName + "\\+", variableValue.toString());
}


Sounds like what you need is the String.format() method:

int total = calculateTotal();
String s = String.format("Your total is %1d.", total);


Not split, but find and replace.

Simplistically,

int variable = 1;
String src = "Your total count is +variable+.";
String result = src.replaceAll("\\+variable\\+.", Integer.toString(variable));
System.out.println(result);

Should print "Your total count is 1."

EDIT: (after your comment) If you need to replace a multiple variables in one go then the following works for me:

// Replace the ff. with the actual map of variables & values
Map<String, String> vars = Collections.singletonMap(
    "variable", Integer.toString(123));

String src = "Your total count is +variable+.";
Pattern p = Pattern.compile("\\+(\\w+)\\+");
StringBuffer sb = new StringBuffer();
Matcher m = p.matcher(src);
while (m.find()) {
    String varName = m.group(1);
    if (vars.containsKey(varName)) {
        m.appendReplacement(sb, vars.get(varName));
    }
}
m.appendTail(sb);
System.out.println(sb.toString());

Prints "Your total count is 123."

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