CODEWITHSUNDEEP
javapattern-matching
Maude
Maude

Reputation: 522

Pattern matching to fetch a value

Suppose I have a String, called text, which contains the following :

blabla="A_VALUE"

Is it possible, with pattern matching, to directly retrieve the value inside the quotation marks?

For example : something similar to Format String, where you could write a pattern, %s, and then get that value.

Right now, a workaround I found is :

text = text.replace("blabla=","");
text = text.replaceAll("\"","");

However, this is very ugly.

Note : It doesn't have to be java, I want to know if the concept exists, and if so, what name does it have.

This post offers some insight, although I'm unsure what \\\\#\\s*(\\S+?)\\s* is suppose to mean

Upvotes: 0

Views: 287

Answers (2)

xtratic
xtratic

Reputation: 4699

Do you mean get the content of strings including any escaped double-quotes?

If so, then this pattern should work for you: "(\\.|[^"])*"

It means: find a double quote then find zero or more occurrences of any escaped character or anything that's not a double-quote until another quote is found.

Broken down:

  • " - find a double quote
  • \\. - find any escaped character
  • [^"] - find any character that's not a double quote
  • (x|y)* - find x or y zero or more times
  • (\\.|[^"])* - find any escaped char or any non-double-quote character zero or more times.

It will find:

Source                        Result
----------------------------+---------------
var str1 = "a string";      | "a string"
var str2 = "a \" string"    | "a \" string"
var str3 = "";              | ""
var str4 = "a string \\";   | "a string \\"

Upvotes: 1

Patrick Parker
Patrick Parker

Reputation: 4959

In there is sscanf which is similar to what you described.

However Java has a Scanner class instead of such a function.

Another alternative is to use Regular Expressions then inspect the relevant Matcher group, as described here: what is the Java equivalent of sscanf for parsing values from a string using a known pattern?

Upvotes: 1

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