Regex replacement in java - java

I'm attempting to make the following replacement in java
#Test
public void testReplace(){
String str = "1JU3C_2.27.CBT";
String find = "(\\d*)\\.(\\d*)";
String replace = "$1,$2";
String modified = str.replaceAll(find, replace);
System.out.println(modified);
assertEquals("1JU3C_2,27.CBT", modified); //fails
}
However both full stops seem to be getting replaced. I'm looking at replacing only the numeric decimal. (i.e expecting output 1JU3C_2,27.CBT)

Use (\\d+)\\.(\\d+) instead of (\\d*)\\.(\\d*).
Your regex asks to replace zero or more digits followed by a dot, followed by zero or more digits. So . in .CBT is matched as it has a dot with zero digits on both sides.
1JU3C_2.27.CBT has two dots with zero or more digits on both sides.
If you want to convert string like 5.67.8 to 5,67,8 use lazy matching as (\\d+?)\\.(\\d+?).

*
stands for zero or more times, try replacing it with
+

Instead do this:
public void testReplace()
{
String str = "1JU3C_2.27.CBT";
String modified = str.replaceFirst("[.]", ",");
System.out.println(modified);
assertEquals("1JU3C_2,27.CBT", modified);
}

Related

How to put new string between commas in original string

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

How can I replace everything between 2nd "." and “:” in java?

Been researching online but haven't been able to find a solution.
I've got the following string '555.8.0.i5:790.2.0.i19:904.1.0:8233.2:' in Java.
Whats the best way I can remove everything from and including the second dot to the colon?
I want the string to end up looking like this: 555.8:790.2:904.1:8233.2:
I saw on another post someone had referenced the second dot with java regex (\d+.\d.) but I'm not sure how to do the trim.
EDIT:
I have tried the following java regex .replaceAll("\\.(.*?):", ":"); but it seems to remove everything from the first dot. Not sure how to get it to trim from the second dot.
In your case, you may use
.replaceAll("(\\.[^:.]+)\\.[^:]+", "$1")
See the regex demo
Details:
(\\.[^:.]+) - Capture group 1 capturing a dot and 1+ chars other than a literal dot and colon
\\. - a literal dot
[^:]+ - 1+ chars other than a colon.
In the replacement pattern, only a $1 backreference to the value captured in Group 1 is used.
Do you have to use regex? Here is a solution using Java:
public static void main(String[] args) {
String myString = "555.8.0.i5:790.2.0.i19:904.1.0:8233.2:";
StringBuilder sb = new StringBuilder();
//Split the string into an array of strings at each colon
String[] stringParts = myString.split(":");
//Loop over each substring
for (String stringPart : stringParts) {
//Find the index of the second dot
int secondDotIndex = stringPart.indexOf('.', 1 + stringPart.indexOf('.', 1));
//If a second dot exists then remove everything after and including the dot
if (secondDotIndex != -1) {
stringPart = stringPart.substring(0, secondDotIndex);
}
//Append each string part and colon back to the final string
sb.append(stringPart);
sb.append(":");
}
System.out.println(sb.toString());
}
The final println prints 555.8:790.2:904.1:8233.2:

Java String- How to get a part of package name in android?

Its basically about getting string value between two characters. SO has many questions related to this. Like:
How to get a part of a string in java?
How to get a string between two characters?
Extract string between two strings in java
and more.
But I felt it quiet confusing while dealing with multiple dots in the string and getting the value between certain two dots.
I have got the package name as :
au.com.newline.myact
I need to get the value between "com." and the next "dot(.)". In this case "newline". I tried
Pattern pattern = Pattern.compile("com.(.*).");
Matcher matcher = pattern.matcher(beforeTask);
while (matcher.find()) {
int ct = matcher.group();
I tried using substrings and IndexOf also. But couldn't get the intended answer. Because the package name in android varies by different number of dots and characters, I cannot use fixed index. Please suggest any idea.
As you probably know (based on .* part in your regex) dot . is special character in regular expressions representing any character (except line separators). So to actually make dot represent only dot you need to escape it. To do so you can place \ before it, or place it inside character class [.].
Also to get only part from parenthesis (.*) you need to select it with proper group index which in your case is 1.
So try with
String beforeTask = "au.com.newline.myact";
Pattern pattern = Pattern.compile("com[.](.*)[.]");
Matcher matcher = pattern.matcher(beforeTask);
while (matcher.find()) {
String ct = matcher.group(1);//remember that regex finds Strings, not int
System.out.println(ct);
}
Output: newline
If you want to get only one element before next . then you need to change greedy behaviour of * quantifier in .* to reluctant by adding ? after it like
Pattern pattern = Pattern.compile("com[.](.*?)[.]");
// ^
Another approach is instead of .* accepting only non-dot characters. They can be represented by negated character class: [^.]*
Pattern pattern = Pattern.compile("com[.]([^.]*)[.]");
If you don't want to use regex you can simply use indexOf method to locate positions of com. and next . after it. Then you can simply substring what you want.
String beforeTask = "au.com.newline.myact.modelact";
int start = beforeTask.indexOf("com.") + 4; // +4 since we also want to skip 'com.' part
int end = beforeTask.indexOf(".", start); //find next `.` after start index
String resutl = beforeTask.substring(start, end);
System.out.println(resutl);
You can use reflections to get the name of any class. For example:
If I have a class Runner in com.some.package and I can run
Runner.class.toString() // string is "com.some.package.Runner"
to get the full name of the class which happens to have a package name inside.
TO get something after 'com' you can use Runner.class.toString().split(".") and then iterate over the returned array with boolean flag
All you have to do is split the strings by "." and then iterate through them until you find one that equals "com". The next string in the array will be what you want.
So your code would look something like:
String[] parts = packageName.split("\\.");
int i = 0;
for(String part : parts) {
if(part.equals("com")
break;
}
++i;
}
String result = parts[i+1];
private String getStringAfterComDot(String packageName) {
String strArr[] = packageName.split("\\.");
for(int i=0; i<strArr.length; i++){
if(strArr[i].equals("com"))
return strArr[i+1];
}
return "";
}
I have done heaps of projects before dealing with websites scraping and I
just have to create my own function/utils to get the job done. Regex might
be an overkill sometimes if you just want to extract a substring from
a given string like the one you have. Below is the function I normally
use to do this kind of task.
private String GetValueFromText(String sText, String sBefore, String sAfter)
{
String sRetValue = "";
int nPos = sText.indexOf(sBefore);
if ( nPos > -1 )
{
int nLast = sText.indexOf(sAfter,nPos+sBefore.length()+1);
if ( nLast > -1)
{
sRetValue = sText.substring(nPos+sBefore.length(),nLast);
}
}
return sRetValue;
}
To use it just do the following:
String sValue = GetValueFromText("au.com.newline.myact", ".com.", ".");

How to replace all numbers in java string

I have string like this String s="ram123",d="ram varma656887"
I want string like ram and ram varma so how to seperate string from combined string
I am trying using regex but it is not working
PersonName.setText(cursor.getString(cursor.getColumnIndex(cursor
.getColumnName(1))).replaceAll("[^0-9]+"));
The correct RegEx for selecting all numbers would be just [0-9], you can skip the +, since you use replaceAll.
However, your usage of replaceAll is wrong, it's defined as follows: replaceAll(String regex, String replacement). The correct code in your example would be: replaceAll("[0-9]", "").
You can use the following regex: \d for representing numbers. In the regex that you use, you have a ^ which will check for any characters other than the charset 0-9
String s="ram123";
System.out.println(s);
/* You don't need the + because you are using the replaceAll method */
s = s.replaceAll("\\d", ""); // or you can also use [0-9]
System.out.println(s);
To remove the numbers, following code will do the trick.
stringname.replaceAll("[0-9]","");
Please do as follows
String name = "ram varma656887";
name = name.replaceAll("[0-9]","");
System.out.println(name);//ram varma
alternatively you can do as
String name = "ram varma656887";
name = name.replaceAll("\\d","");
System.out.println(name);//ram varma
also something like given will work for you
String given = "ram varma656887";
String[] arr = given.split("\\d");
String data = new String();
for(String x : arr){
data = data+x;
}
System.out.println(data);//ram varma
i think you missed the second argument of replace all. You need to put a empty string as argument 2 instead of actually leaving it empty.
try
replaceAll(<your regexp>,"")
you can use Java - String replaceAll() Method.
This method replaces each substring of this string that matches the given regular expression with the given replacement.
Here is the syntax of this method:
public String replaceAll(String regex, String replacement)
Here is the detail of parameters:
regex -- the regular expression to which this string is to be matched.
replacement -- the string which would replace found expression.
Return Value:
This method returns the resulting String.
for your question use this
String s = "ram123", d = "ram varma656887";
System.out.println("s" + s.replaceAll("[0-9]", ""));
System.out.println("d" + d.replaceAll("[0-9]", ""));

having trouble with arrays and maybe split

String realstring = "&&&.&&&&";
Double value = 555.55555;
String[] arraystring = realstring.split(".");
String stringvalue = String.valueof(value);
String [] valuearrayed = stringvalue.split(".");
System.out.println(arraystring[0]);
Sorry if it looks bad. Rewrote on my phone. I keep getting ArrayIndexOutOfBoundsException: 0 at the System.out.println. I have looked and can't figure it out. Thanks for the help.
split() takes a regexp as argument, not a literal string. You have to escape the dot:
string.split("\\.");
or
string.split(Pattern.quote("."));
Or you could also simply use indexOf('.') and substring() to get the two parts of your string.
And if the goal is to get the integer part of a double, you could also simply use
long truncated = (long) doubleValue;
split uses regex as parameter and in regex . means "any character except line separators", so you could expect that "a.bc".split(".") would create array of empty strings like ["","","","",""]. Only reason it is not happening is because (from split javadoc)
This method works as if by invoking the two-argument split method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.
so because all strings are empty you get empty array (and that is because you see ArrayIndexOutOfBoundsException).
To turn off removal mechanism you would have to use split(regex, limit) version with negative limit.
To split on . literal you need to escape it with \. (which in Java needs to be written as "\\." because \ is also Strings metacharacter) or [.] or other regex mechanism.
Dot (.) is a special character so you need to escape it.
String realstring = "&&&.&&&&";
String[] partsOfString = realstring.split("\\.");
String part1 = partsOfString[0];
String part2 = partsOfString[1];
System.out.println(part1);
this will print expected result of
&&&
Its also handy to test if given string contains this character. You can do this by doing :
if (string.contains(".")) {
// Split it.
} else {
throw new IllegalArgumentException("String " + string + " does not contain .");
}

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