CODEWITHSUNDEEP
javaregex
Ashesh Nair
Ashesh Nair

Reputation: 327

Pattern Matching - Regex in Java

I am looking for Regex Pattern extraction to extract the following example ,

sample Input: 
"USER 1-EFA-Thermal Analysis-0.25;USER 2-EFA-Thermal Analysis-0.25;"

 String[] parts = filename.split("\\;");
    for (int i=0;i<=parts.length;i++){

    }

The above code split the line into Multiple part with ";" as delimiter. Inside the For Loop i want to again the split each part[] into three phrases which is identified by "-" (dash).But problem being the Dash can also appear within the field to be separated .

So my logic to is to split the Words Before First occurrence of "-" as 1st Part.

String After First Occurrence of "dash" till last occurrence of "dash" as 2nd And the remaining being 3rd Part

For example :

part[0]
USER 1
EFA-Thermal Analysis
0.25

part[1]
USER 2
EFA-Thermal Analysis
0.25

Upvotes: 1

Views: 107

Answers (2)

bro
bro

Reputation: 771

Use a regex to match everything until the first "minus": 

part.replaceAll("^([^\\-]*)-", "$1\n")

and everything from the last minus until the end of the string:

part.replaceAll("-([^\\-]*?)$", "\n$1")

Code

String sample = "USER 1-EFA-Thermal Analysis-0.25;USER 2-EFA-Thermal Analysis-0.25;";
String[] parts = sample.split("\\;");

for (String part : parts) {
    part = part.replaceAll("^([^\\-]*)-", "$1\n");
    part = part.replaceAll("-([^\\-]*?)$", "\n$1");
    System.out.println(part);
}

Output

USER 1
EFA-Thermal Analysis
0.25
USER 2
EFA-Thermal Analysis
0.25

Demo on ideone

Upvotes: 2

npinti
npinti

Reputation: 52185

The .split(string regex) method will most likely not work, at least I cannot see how it can be used to achieve a relatively simple solution. The problem, in my opinion is that the dash can appear in between different character types which makes it tricky to latch onto.

I managed to achieve what you are after through a slightly different usage of regular expressions:

String str = "USER 1-EFA-Thermal Analysis-0.25;USER 2-EFA-Thermal Analysis-0.25;";
Pattern pattern = Pattern.compile("(.+?)-(.+?)-(\\d+(\\.\\d+)?);");
Matcher matcher = pattern.matcher(str);
while(matcher.find())
    System.out.println(matcher.group(1) + " " + matcher.group(2) + " " + matcher.group(3));

The code below yields the following information:

USER 1 EFA-Thermal Analysis 0.25
USER 2 EFA-Thermal Analysis 0.25

Which, according to the samples you have provided, should do what you are after. An example of the regular expression is available here.

Upvotes: 3

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