String = "9,3,5,*****,1,2,3"
I'd like to simply access "5", which is between two commas, and right before "*****"; then only replace this "5" to other value.
How could I do this in Java?
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Nothing. I know s.split; s.replace; s.substring; but How can I first split and then replace?LookIntoEast– LookIntoEast2017-07-22 06:22:57 +00:00Commented Jul 22, 2017 at 6:22
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You should ask question based on what you have tried and the problem you are facing. You can use regex pattern like this String pattern = ".*(\\d),\*+"; and create a on that regex Pattern r = Pattern.compile(pattern); now run matcher object against the text Matcher m = r.matcher(text); If you group by capture group after checking if any thing found by m.find() then m.group(1) will contain your value. Do Read RegEx & Capturing group in java.Check this SO question stackoverflow.com/questions/17969436/…prajitgandhi– prajitgandhi2017-07-22 06:35:48 +00:00Commented Jul 22, 2017 at 6:35
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5 Answers
You can try using the following regex replacement:
String input = "9,3,5,*****,1,2,3";
input = input.replaceAll("[^,]*,\\*{5}", "X,*****");
Here is an explanation of the regex:
[^,]*, match any number of non-comma characters, followed by one comma
\\*{5} followed by five asterisks
This means to match whatever CSV term plus a comma comes before the five asterisks in your string. We then replace this with what you want, along with the five stars in the original pattern.
Demo here:
Rextester
2 Comments
Dawood ibn Kareem
My apologies, @Tim. I messed up, then we clashed. Very sorry. I'm not really trying to be a vandal.
LookIntoEast
Many thanks. But could you explain a little bit about "\*{5}" ? What does it mean?
I'd use a regular expression with a lookahead, to find a string of digits that precedes ",*****", and replace it with the new value. The regular expression you're looking for would be \d+(?=,\*{5}) - that is, one or more digits, with a lookahead consisting of a comma and five asterisks. So you'd write
newString = oldString.replaceAll("\\d+(?=,\\*{5})", "replacement");
Here is an explanation of the regex pattern used in the replacement:
\\d+ match any numbers of digits, but only when
(?=,\\*{5}) we can lookahead and assert that what follows immediately
is a single comma followed by five asterisks
It is important to note that the lookahead (?=,\\*{5}) asserts but does not consume. Hence, we can ignore it with regards to the replacement.
answered Jul 22, 2017 at 6:35
Dawood ibn Kareem
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1 Comment
LookIntoEast
thx. \\d+ means digits; while \*{5} means five asterisks.But i'm still vague about +(?= part; what does it mean?
I considered newstr be "6"
String str = "9,3,5,*****,1,2,3";
char newstr = '6';
str = str.replace(str.charAt(str.indexOf(",*") - 1), newstr);
Also if you are not sure about str length check for IndexOutOfBoundException and handle it
Comments
You could split on , and then join with a , (after replacing 5 with the desired value - say X). Like,
String[] arr = "9,3,5,*****,1,2,3".split(",");
arr[2] = "X";
System.out.println(String.join(",", arr));
Which outputs
9,3,X,*****,1,2,3
2 Comments
Dawood ibn Kareem
I think OP is interested in finding the
***** and replacing the element before it, regardless of its position in the array.
Elliott Frisch
@DawoodibnKareem between two commas, and right before
"*****"; - so it seems the index is fixed (to me).you can use spit() for replacing a string
String str = "9,3,5,*****,1,2,3";
String[] myStrings = str.split(",");
String str1 = myStrings[2];
