Develop Reference

Splitting string on spaces unless in double quotes but double quotes can have a preceding string attached

I need to split a string in Java (first remove whitespaces between quotes and then split at whitespaces.)
"abc test=\"x y z\" magic=\" hello \" hola"
becomes:
firstly:
"abc test=\"xyz\" magic=\"hello\" hola"
and then:
abc
test="xyz"
magic="hello"
hola
Scenario :
I am getting a string something like above from input and I want to break it into parts as above. One way to approach was first remove the spaces between quotes and then split at spaces. Also string before quotes complicates it. Second one was split at spaces but not if inside quote and then remove spaces from individual split. I tried capturing quotes with "\"([^\"]+)\"" but I'm not able to capture just the spaces inside quotes. I tried some more but no luck.

We can do this using a formal pattern matcher. The secret sauce of the answer below is to use the not-much-used Matcher#appendReplacement method. We pause at each match, and then append a custom replacement of anything appearing inside two pairs of quotes. The custom method removeSpaces() strips all whitespace from each quoted term.
public static String removeSpaces(String input) {
return input.replaceAll("\\s+", "");
}
String input = "abc test=\"x y z\" magic=\" hello \" hola";
Pattern p = Pattern.compile("\"(.*?)\"");
Matcher m = p.matcher(input);
StringBuffer sb = new StringBuffer("");
while (m.find()) {
m.appendReplacement(sb, "\"" + removeSpaces(m.group(1)) + "\"");
}
m.appendTail(sb);
String[] parts = sb.toString().split("\\s+");
for (String part : parts) {
System.out.println(part);
}
abc
test="xyz"
magic="hello"
hola
Demo
The big caveat here, as the above comments hinted at, is that we are really using a regex engine as a rudimentary parser. To see where my solution would fail fast, just remove one of the quotes by accident from a quoted term. But, if you are sure you input is well formed as you have showed us, this answer might work for you.

I wanted to mention the java 9's Matcher.replaceAll lambda extension:
// Find quoted strings and remove there whitespace:
s = Pattern.compile("\"[^\"]*\"").matcher(s)
.replaceAll(mr -> mr.group().replaceAll("\\s", ""));
// Turn the remaining whitespace in a comma and brace all.
s = '{' + s.trim().replaceAll("\\s+", ", ") + '}';

Probably the other answer is better but still I have written it so I will post it here ;) It takes a different approach
public static void main(String[] args) {
String test="abc test=\"x y z\" magic=\" hello \" hola";
Pattern pattern = Pattern.compile("([^\\\"]+=\\\"[^\\\"]+\\\" )");
Matcher matcher = pattern.matcher(test);
int lastIndex=0;
while(matcher.find()) {
String[] parts=matcher.group(0).trim().split("=");
boolean newLine=false;
for (String string : parts[0].split("\\s+")) {
if(newLine)
System.out.println();
newLine=true;
System.out.print(string);
}
System.out.println("="+parts[1].replaceAll("\\s",""));
lastIndex=matcher.end();
}
System.out.println(test.substring(lastIndex).trim());
}
Result is
abc
test="xyz"
magic="hello"
hola

It sounds like you want to write a basic parser/Tokenizer. My bet is that after you make something that can deal with pretty printing in this structure, you will soon want to start validating that there arn't any mis-matching "'s.
But in essence, you have a few stages for this particular problem, and Java has a built in tokenizer that can prove useful.
import java.util.LinkedList;
import java.util.List;
import java.util.StringTokenizer;
import java.util.stream.Collectors;
public class Q50151376{
private static class Whitespace{
Whitespace(){ }
#Override
public String toString() {
return "\n";
}
}
private static class QuotedString {
public final String string;
QuotedString(String string) {
this.string = "\"" + string.trim() + "\"";
}
#Override
public String toString() {
return string;
}
}
public static void main(String[] args) {
String test = "abc test=\"x y z\" magic=\" hello \" hola";
StringTokenizer tokenizer = new StringTokenizer(test, "\"");
boolean inQuotes = false;
List<Object> out = new LinkedList<>();
while (tokenizer.hasMoreTokens()) {
final String token = tokenizer.nextToken();
if (inQuotes) {
out.add(new QuotedString(token));
} else {
out.addAll(TokenizeWhitespace(token));
}
inQuotes = !inQuotes;
}
System.out.println(joinAsStrings(out));
}
private static String joinAsStrings(List<Object> out) {
return out.stream()
.map(Object::toString)
.collect(Collectors.joining());
}
public static List<Object> TokenizeWhitespace(String in){
List<Object> out = new LinkedList<>();
StringTokenizer tokenizer = new StringTokenizer(in, " ", true);
boolean ignoreWhitespace = false;
while (tokenizer.hasMoreTokens()){
String token = tokenizer.nextToken();
boolean whitespace = token.equals(" ");
if(!whitespace){
out.add(token);
ignoreWhitespace = false;
} else if(!ignoreWhitespace) {
out.add(new Whitespace());
ignoreWhitespace = true;
}
}
return out;
}
}

How to replace special character In Android?

I have to create file with user define name. If User can use the special character then i want to replace that special character with my specific string. i found the method like this.
String replaceString(String string) {
return string.replaceAll("special_char","");
}
but how to use this method.?

relpaceAll method is required regular expression and replace string.
string.replaceAll("regularExpression","replaceString");
You can use this regular expression :
"[;\\/:*?\"<>|&']"
e.g.
String replaceString(String string) {
return string.replaceAll("[;\\/:*?\"<>|&']","replaceString");
}

Try
regular expression
static String replaceString(String string) {
return string.replaceAll("[^A-Za-z0-9 ]","");// removing all special character.
}
call
public static void main(String[] args) {
String str=replaceString("Hello\t\t\t.. how\t\t are\t you."); // call to replace special character.
System.out.println(str);
}
output:
Hello how are you

use below function to replace your string
public static String getString(String p_value)
{
String p_value1 = p_value;
if(p_value1 != null && ! p_value1.isEmpty())
{
p_value1 = p_value1.replace("Replace string from", "Replace String to");
return p_value1;
}
else
{
return "";
}
}
example
Replace string from = "\n";
Replace String to = "\r\n";
after using above function \n is replace with \r\n

**this method make two line your string data after specific word **
public static String makeTwoPart(String data, String cutAfterThisWord){
String result = "";
String val1 = data.substring(0, data.indexOf(cutAfterThisWord));
String va12 = data.substring(val1.length(), data.length());
String secondWord = va12.replace(cutAfterThisWord, "");
Log.d("VAL_2", secondWord);
String firstWord = data.replace(secondWord, "");
Log.d("VAL_1", firstWord);
result = firstWord + "\n" + secondWord;
return result;
}

How do you print out a string exactly as it is?

I had an issue with my code because my file path somehow ended up with a "\n" at the end of the path which caused issues when trying to use the file, as it would not be able to find that file.
For debugging purposes, how can I print out a string INCLUDING things like \b \n \r etc.?
E.g.
System.out.println(file.getAbsolutePath).withSpecials()
which will print to console:
C:/folder/filename.extension\n

You could try using this code, which escapes a string. This takes care of all escapes except \u, which should display fine anyway.
public static String escape(String str) {
str = str.replace("\b", "\\b");
str = str.replace("\t", "\\t");
str = str.replace("\n", "\\n");
str = str.replace("\r", "\\r");
str = str.replace("\f", "\\f");
str = str.replace("\'", "\\'");
str = str.replace("\\", "\\\\");
return str;
}
This function can be used as follows:
System.out.println(escape("123\n\rabc"));

public class Main {
public static void main(String arg[]) {
String str = "bla\r\n";
System.out.print(str); // prints "bla" and breaks line
System.out.print(Main.withEndings(str)); // prints "bla\r\n"
// Breaks a line
System.out.println();
// Every char is a number, Java uses by default UTF-16 char encoding
char end = '\n';
System.out.println("Char code: " + (int)end); // prints "Char code: 10"
}
public static String withEndings(String str) {
// Replace the character '\n' to a string with 2 characters the '\' and the 'n',
// the same to '\r'.
return str.replace("\n", "\\n").replace("\r", "\\r");
}
}

You can print the \n by doing string.replace("\n", "\\\\n");
So to print it out do: System.out.println(file.getAbsolutePath().replace("\n", "\\\\n"));

SubString replacement in text

I want to replace all the occurrences of a string in a text except the first one.
for eg:
input: Example [2] This is a sample text. This is a sample text. This is a sample text.
replaced word: sample (sImple)
output: Example [2] This is a sample text. This is a sImple text. This is a sImple text.
In string functions what I see is replace, replaceAll, replaceFirst.
How should I handle this case.
Thanks in advance.

You can use this regex to search:
((?:\bsample\b|(?<!^)\G).*?)\bsample\b
And this for replcement:
$1simple
RegEx Demo
Java Code:
String r = input.replaceAll("((?:\\bsample\\b|(?<!^)\\G).*?)\\bsample\\b", "$1simple");

replaceAll and replace will replace all substrings (difference between them is that replaceAll uses regular expression as argument, while replace uses literals).
replaceFirst will replace only first substring which will match pattern you want to find.
What you can do is
use indexOf(String str, int fromIndex) method to determine indexes of first and second sample word,
then substring(int beginIndex) on index of second sample to get part of string from which you want to let replacing possible
and call your replace method on this part
when replacement is done you can concatenate part which shouldn't be changed (before index of second sample word) and part with replaced values
Other solution would be using appendReplacement and appendTail form Matcher class and use replacing value after you find second sample word. Code for it can look like
String yourString = "Example [2] This is a sample text. This is a sample text. This is a sample text.";
Pattern p = Pattern.compile("sample", Pattern.LITERAL);
Matcher m = p.matcher(yourString);
StringBuffer sb = new StringBuffer();
boolean firstWordAlreadyFound = false;
while (m.find()) {
if (firstWordAlreadyFound) {
m.appendReplacement(sb, "sImple");
} else {
m.appendReplacement(sb, m.group());
firstWordAlreadyFound = true;
}
}
m.appendTail(sb);
String result = sb.toString();
System.out.println(result);
Output:
Example [2] This is a sample text. This is a sImple text. This is a sImple text.

Here is a naive approach:
public static String replaceAllButFirst(String text, String toReplace, String replacement) {
String[] parts = text.split(toReplace, 2);
if(parts.length == 2) { //Found at least one match
return parts[0] + toReplace + parts[1].replaceAll(toReplace, replacement);
} else { //no match found giving original text
return text;
}
}
public static void main(String[] args) {
String x = "This is a sample test. This is a sample test. This is a sample test";
System.out.println(replaceAllButFirst(x, "sample", "simple"));
}
Which will give:
This is a sample test. This is a simple test. This is a simple test

Try with substring and indexOf methods to break it in two string then replace in second string and finally append both the strings back
sample code:
String str = "Example [2] This is a sample text. This is a sample text. This is a sample text.";
String findWhat = "sample";
int index = str.indexOf(findWhat) + findWhat.length();
String temp = str.substring(0, index + 1); // first string
str = str.substring(index + 1); // second string
//replace in second string and combine back
str = temp + str.replace(findWhat, "simple"); // final string
System.out.println(str);
combine all in few statements:
int index = str.indexOf(findWhat) + findWhat.length();
str = str.substring(0, index + 1) + str.substring(index + 1).replace(findWhat, "simple");

There is no built-in function that does exactly what you want, either in the String or StringBuilder classes. You'll need to write your own. Here's a quickie:
private string ReplaceText(string originalText, string textToReplace, string replacementText)
{
string tempText;
int firstIndex, lastIndex;
tempText = originalText;
firstIndex = originalText.IndexOf(textToReplace);
lastIndex = tempText.LastIndexOf(textToReplace);
while (firstIndex >= 0 && lastIndex > firstIndex)
{
tempText = tempText.Substring(0,lastIndex) + replacementText + tempText.Substring(lastIndex + textToReplace.Length);
lastIndex = tempText.LastIndexOf(textToReplace);
}
return tempText;
}

Another option:
(?<=\bsample\b)(.*?)\bsample\b
And replacement:
$1yourstring
Java Code:
String s=input.replaceAll("(?<=\\bsample\\b)(.*?)\\bsample\\b", "$1yourString");

Java : Replacing Last character of a String and First character of the String

I want to add Two java JSON String manually , so for this i need to remove "}" and replace it with comma "," of first JSON String and remove the first "{" of the second JSON String .
This is my program
import java.util.Map;
import org.codehaus.jackson.type.TypeReference;
public class Hi {
private static JsonHelper jsonHelper = JsonHelper.getInstance();
public static void main(String[] args) throws Exception {
Map<String, Tracker> allCusts = null;
String A = "{\"user5\":{\"Iden\":4,\"Num\":1},\"user2\":{\"Iden\":5,\"Num\":1}}";
String B = "{\"user1\":{\"Iden\":4,\"Num\":1},\"user3\":{\"Iden\":6,\"Num\":1},\"user2\":{\"Iden\":5,\"Num\":1}}";
String totalString = A + B;
if (null != totalString) {
allCusts = (Map<String, Tracker>) jsonHelper.toObject(
totalString, new TypeReference<Map<String, Tracker>>() {
});
}
System.out.println(allCusts);
}
}
When adding two Strings A + B
I want to remove the last character of "}" in A and replace it with "," and remove the FIrst character of "{" in B .
SO this should it look like .
String A = "{\"user5\":{\"Iden\":4,\"Num\":1},\"user2\":{\"Iden\":5,\"Num\":1},";
String B = "\"user1\":{\"Iden\":4,\"Num\":1},\"user3\":{\"Iden\":6,\"Num\":1},\"user2\":{\"Iden\":5,\"Num\":1}}";
I have tried
String Astr = A.replace(A.substring(A.length()-1), ",");
String Bstr = B.replaceFirst("{", "");
String totalString = Astr + Bstr ;
With this i was getting
Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal repetition
please suggest .

{ is a control character for Regular Expressions, and since replaceFirst takes a string representation of a Regular Expression as its first argument, you need to escape the { so it's not treated as a control character:
String Bstr = B.replaceFirst("\\{", "");
I would say that using the replace methods is really overkill here since you're just trying to chop a character off of either end of a string. This should work just as well:
String totalString = A.substring(0, A.length()-1) + "," + B.substring(1);

Of course, regex doesn't look like a very good tool for this. But the following seem to work:
String str = "{..{...}..}}";
str = str.replaceFirst("\\{", "");
str = str.replaceFirst("}$", ",");
System.out.println(str);
Output:
..{...}..},

Some issues in your first two statements. Add 0 as start index in substring method and leave with that. Put \\ as escape char in matching pattern and ut a , in second statement as replacement value.
String Astr = A.substring(0, A.length()-1);//truncate the ending `}`
String Bstr = B.replaceFirst("\\{", ",");//replaces first '{` with a ','
String totalString = Astr + Bstr ;
Please note: There are better ways, but I am just trying to correct your statements.