This question already has answers here:
Replace the last part of a string
(11 answers)
Closed 8 years ago.
Let's say I have a string
string myWord="AAAAA";
I want to replace "AA" with "BB", but only the last occurrence, like so:
"AAABB"
Neither string.replace() nor string.replaceFirst() would do the job.
Is there a string.replaceLast()? And, If not, will there ever be one or is there an alternative also working with regexes?
Find the index of the last occurrence of the substring.
String myWord = "AAAAAasdas";
String toReplace = "AA";
String replacement = "BBB";
int start = myWord.lastIndexOf(toReplace);
Create a StringBuilder (you can just concatenate Strings if you wanted to).
StringBuilder builder = new StringBuilder();
Append the part before the last occurrence.
builder.append(myWord.substring(0, start));
Append the String you want to use as a replacement.
builder.append(replacement);
Append the part after the last occurrence from the original `String.
builder.append(myWord.substring(start + toReplace.length()));
And you're done.
System.out.println(builder);
You can do this:
myWord = myWord.replaceAll("AA$","BB");
$ means at the last.
Just get the last index and do an in place replacement of the expression with what you want to replace.
myWord is the original word sayAABDCAADEF. sourceWord is what you want to replace, say AA
targetWord is what you want to replace it with say BB.
StringBuilder strb=new StringBuilder(myWord);
int index=strb.lastIndexOf(sourceWord);
strb.replace(index,sourceWord.length()+index,targetWord);
return strb.toString();
This is useful when you want to just replace strings with Strings.A better way to do it is to use Pattern matcher and find the last matching index. Take as substring from that index, use the replace function there and then add it back to the original String. This will help you to replace regular expressions as well
String string = "AAAAA";
String reverse = new StringBuffer(string).reverse().toString();
reverse = reverse.replaceFirst(...) // you need to reverse needle and replacement string aswell!
string = new StringBuffer(reverse).reverse().toString();
It seems like there could be a regex answer to this.
I initially was trying to solve this through regex, but could not solve for situations like 'AAAzzA'.
So I came up with this answer below, which can handle both 'AAAAA' and 'AAAzzA'. This may not be the best answer, but I guess it works.
The basic idea is to find the last index of 'AA' occurrence and split string by that index:
String myWord = "AAAAAzzA";
String source = "AA";
String target = "BB";
int lastIndex = -1;
if ((lastIndex = myWord.lastIndexOf(source)) >= 0) {
String f = myWord.substring(0, lastIndex);
String b = myWord.substring(lastIndex + target.length() >= myWord
.length() ? myWord.length() : lastIndex + target.length(),
myWord.length());
myWord = f + target + b;
}
System.out.println(myWord);
myWord=myWord.replaceAll("AA(?!A)","BB");
You can do this with String#subtring
myWord= myWord.substring(0, myWord.length() - 2) + "BB";
Related
I have this original string and I want to insert new string between two dots of original string. I did it this way, but having errors.
String originalString ="asdASfasdlpe.hereNeedToPutNewString.asdasfdfepw";
String stringForReplace = "NewString";
String new = originalString.replace(originalString.substring(originalString.indexOf(".") + 1), stringForReplace);
it gives me: "asdASfasdlpe.NewString"
Result should be: "asdASfasdlpe.NewString.asdasfdfepw"
I would do it like so.
from the question it looks like you want to replace the first occurrence so use replaceFirst
(?<=\\.) - look behind assertion - so start with following character
(?=\\.) - look ahead assertion - so end prior to that
.*? - reluctant quantifier to limit to just characters between two periods. Use * in case you have two adjacent periods since the string could be empty.
String s = "first.oldstring.third.fourth.fifth";
String n = "second";
s = s.replaceFirst("(?<=\\.).*?(?=\\.)",n);
System.out.println(s);
prints
first.second.third.fourth.fifth
String originalString ="asdASfasdlpe.hereNeedToPutNewString.asdasfdfepw";
String stringForReplace = "NewString";
String a[]=originalString.split("[.]");
String newString="";
if(a.length==3) {
newString=originalString.replace(a[1], stringForReplace);
}
System.out.println(newString);
Or with ternary operator:
newString=(a.length== 3 ? originalString.replace(a[1], stringForReplace):null);
System.out.println(newString);
One shorter solution is to use regex with a lookahead and lookbehind
String replaced = originalString.replaceAll("(?<=\\.).+(?=\\.)", stringForReplace);
The problem with your code is due to using this particular piece of code:
originalString.substring(originalString.indexOf(".") + 1)
The reason is that indexof() function will only give the index on which "." was found on, and substring will only know where to start taking the substring from, but it wouldn't know where to end it.
Try this:
String originalString ="asdASfasdlpe.hereNeedToPutNewString.asdasfdfepw";
String stringForReplace = "NewString";
String newString = originalString.replace(originalString.split("[.]", 3)[1], stringForReplace);
System.out.println(newString);
The split function in this piece of code will break the whole string by "."
and you will have the string you want to replace available to you.
originalString.split("[.]", 3)[1]
You could try the following:
public static void main(String[] args) {
String originalString ="asdASfasdlpe.hereNeedToPutNewString.asdasfdfepw";
String stringForReplace = "NewString";
String newStr = originalString.replaceAll("(?<=\\.).*(?=\\.)", stringForReplace);
//using lookahead and lookbehind regex
String newStr2 = originalString.replaceAll("\\..*\\.", "."+stringForReplace+".");
System.out.println(newStr);
System.out.println(newStr2);
}
One option uses lookahead and lookbehinds, you could opt to not use that if it is not supported.
Output:
asdASfasdlpe.NewString.asdasfdfepw
asdASfasdlpe.NewString.asdasfdfepw
Here You go:
String new = originalString.replace(originalString.substring(originalString.indexOf(".") + 1), stringForReplace)+originalString.substring(originalString.indexOf(".",originalString.indexOf(".")+1),originalString.length());
What I have done is adding the resultant string to the new String.indexOf function takes another argument too, which is the position the search will start
I try to replace a character and all it's following characters within a string with another character.
This is my code so far.
String name = "Peter Pan";
name = name.replace("er", "abc");
Log.d("Name", name)
the result should be: "Petabc"
I would highly appreciate any help on this matter!
A way to achive your goal:
search the string for the first appearance of the sequnce you want to replace
use that index and cut the string using String#substring
add your replace sequence to the end of the substring you just created
fin.
Good luck.
EDIT
In code it might look like this (not tested)
public static String customReplace(String input, String replace)
{
int index = input.indexOf(replace);
if(index >= 0)
{
return input.substring(index) + replace; //cutting string down to the required part and adding the replace
}
else
return null; //String 'input' doesn't contain String 'replace'
}
You could use a Regular Expression here with String's built-in replaceAll method to very easily do what you want:
original.replaceFirst(toReplace + ".*", replaceWith);
For example:
String original = "testing 123";
String toReplace = "ing";
String replaceWith = "er";
String replaced = original.replaceFirst(toReplace + ".*", replaceWith);
After the above, replaced will be set to "tester".
i have a string sssssh and i want to get the result as h only. it only can solve while i have another string ssssth and i will get th also without the s in front. whether i need to split it? can anyone help me?
i don't want to use - to separate by inserting the split coding since my string is like this.
before this i originally the string is h then i using String.format to insert ssss in front of the h. lastly i need to remove all the s and get the original string h.
String str1 = ssssh;
String result = h;
You could use the String method to get the index of the last character 's':
int lastOccurenceOfS = str1.lastIndexOf("s");
Then you split your string from the next character forward:
String endString = str1.subString(lastOccurenceOfS + 1);
If what your asking is to split the h from all the other characters you can use this:
String str1 = "ssssh";
char ch = str1.charAt(str1.length() - 1);
Then what you are left with is the Char ch(h)
I have a string like this :
12
I want to get split to [2] ignoring 1. Is it possible to do so in java?
You can use the split() method to split on a regex input or, better yet, if you know the exact position or character you want to split at (as seems to be the case here), just use substring() combined with indexOf(). Something like:
String substring = string.substring(0, indexOf("2"));
where string is your original String variable..
If you know the exact index,
String str = "12"
String s = str.substring(1,2); // output 2
or
String s = str.substring(0, indexOf("2")); //output 2
or
char[] chars = str.toCharArray();
char c = chars[1]; // output
This question already has answers here:
How can I check if a single character appears in a string?
(16 answers)
Closed 6 years ago.
I want to check if my string contains a + character.I tried following code
s= "ddjdjdj+kfkfkf";
if(s.contains ("\\+"){
String parts[] = s.split("\\+);
s= parts[0]; // i want to strip part after +
}
but it doesnot give expected result.Any idea?
You need this instead:
if(s.contains("+"))
contains() method of String class does not take regular expression as a parameter, it takes normal text.
EDIT:
String s = "ddjdjdj+kfkfkf";
if(s.contains("+"))
{
String parts[] = s.split("\\+");
System.out.print(parts[0]);
}
OUTPUT:
ddjdjdj
Why not just:
int plusIndex = s.indexOf("+");
if (plusIndex != -1) {
String before = s.substring(0, plusIndex);
// Use before
}
It's not really clear why your original version didn't work, but then you didn't say what actually happened. If you want to split not using regular expressions, I'd personally use Guava:
Iterable<String> bits = Splitter.on('+').split(s);
String firstPart = Iterables.getFirst(bits, "");
If you're going to use split (either the built-in version or Guava) you don't need to check whether it contains + first - if it doesn't there'll only be one result anyway. Obviously there's a question of efficiency, but it's simpler code:
// Calling split unconditionally
String[] parts = s.split("\\+");
s = parts[0];
Note that writing String[] parts is preferred over String parts[] - it's much more idiomatic Java code.
[+]is simpler
String s = "ddjdjdj+kfkfkf";
if(s.contains ("+"))
{
String parts[] = s.split("[+]");
s = parts[0]; // i want to strip part after +
}
System.out.println(s);