Im trying to use a question mark as a variable for a string.
I've tried...
strings.xml
<string name="questionMark">\?</string>
.class
String questionMark;
questionMark = getResources().getString(R.string.questionMark);
String delim4 = (questionMark);
This causes a fource close regex error.
and
String delim4 = (\?);
This gets an error Invalid escape sequence (valid ones are \b \t \n \f \r \" \' \ )
and also
I've tried putting 2 backslashes in front of it
String delim4 =(\\?)
System.out.println("delim "+ delim4);
But that just escapes the second slash and sometimes force closes as well.
the output for that was
delim \?
Can any tell me how to put in the question mark as the string. I'm using it as variable to spit a string. The String Im splitting can not be changed.
plz help
Edit added split code
if (FinishedUrl.contains(questionMark)){
String delim3 = (".com/");
String[] parts3 = FinishedUrl.split(delim3);
String JUNK3= parts3[0];
String fIdStpOne = parts3[1];
String fIdStpTwo = fIdStpOne.replaceAll("=#!/","");
String delim4 = (questionMark);
String[] parts4 = fIdStpTwo.split(delim4);
String fIdStpThree= parts3[0];
String JUNK4 = parts3[1];
FId = fIdStpThree;
}
As pointed out by user laalto, ? is a meta-character in regex. You must work around that.
Let's see what's happening here. Firstly, some ground rules:
`?` is not a special character in Java
`?` is a reserved character in regex
This entails:
String test = "?"; // Valid statement in java, but illegal when used as a regex
String test = "\?"; // Illegal use of escape character
Why is the second statement wrong? Because we are trying to escape a character that isn't special (in Java). Okay, we'll get back to this.
Now, for the split(String) method, we need to escape the ? - it being a meta-character in regex. So, we need \? for the regex.
Coming back to the string, how do we get \?? We need to escape the \(backslash) - not the question mark!
Here's the workflow:
String delim4 = "\\?";
This statement gives us \? - it escapes the \(backslash).
String[] parts4 = fIdStpTwo.split(delim4);
This lets us use \? as a regex in the split() method. Since delim4 is being passed as a regex, \? is used as ?. Here, the prefix \ is used to escape ?.
Your observations:
String delim4 = (\?);
This gets an error Invalid escape sequence (valid ones are \b \t \n \f \r \" \' \ )
I covered this above. You are escaping ? at the java level - but it isn't a special character and needs no escaping - hence the error.
String delim4 =(\\?)
System.out.println("delim "+ delim4);
But that just escapes the second slash and sometimes force closes as well. the output for that was
delim \?
This is what we want. It is easier to think of this as a two stage process. The first stage deals with successfully placing a \(backslash) in front of the ?. In the second stage, regex finds that the ? has been prefixed by a \ and uses ? as a literal instead of a meta-character.
And here's how you can place the regex in your res/values/strings.xml:
<string name="questionMark">\\?</string>
By the way, there's another option - not something I use on a regular basis these days - split() works just fine.
You can use StringTokenizer which works with delimiters instead of regex. Afaik, any literal can be used as a delimiter. So, you can use ? directly:
StringTokenizer st = new StringTokenizer(stringToSplit, "?");
while (st.hasMoreTokens()) {
// Use tokens
String token = st.nextToken();
}
Easiest way is to quote or backslash them:
<string name="random">"?"</string>
<string name="random">\?</string>
The final code.
String startDelim = ("\\?");
String realDelim = (startDelim);
String[] parts4 = fIdStpOne.split(realDelim);
String fIdStpTwo= parts4[0];
String JUNK4 = parts4[1];
Normally you'd just put it literally, like
String q = "?";
However, you say you're using it to split a string. split() takes a regular expression and ? is a metacharacter in a regex. To escape it, add a backslash in front. Backslash is a special character in Java string literals so it needs to be escaped, too:
String q = "\\?";
Related
I want to put extra value from intent to other intent. But in other intent, app get all value. Example:
mAddress.setText(" from " + address);
String put_address = mAddress.getText().toString();
editIntent.putExtra("put_address", put_address);
is it possible to cut text "from" and get only address variable ???
you can split a string like
str = "From address#dd.com";
String modified = str.replace;
now splitstr contain your split strings
splitStr[1] contains "address#dd.com"
Can also use
str.substring(str.indexOf(" ")+1);
By the way, you can use jagapathi's answer. In his example he uses regular expression.
Regular expressions can help to parse, find, cut substrings using a particular pattern. In his code he splits string by any space character.
But, imho, the simplest solution is to create a substring using this code:
'put_address.substring(7);'
use one of these solutions:
String input = put_address.trim().substring(5);
*** note: 5 is index of real address first character;
String input = put_address..split(" ")[1];
I have a problem with one line of code, which goes like this:
string = string.replaceAll("sin()", "");
As you can see, in a string, all "sin()" need to be replaced with "". But the problem is that () is not treated as string and so this line of code replaces "sin()" with "()". Moreover, Android studio reports warning on the () saying empty group. I tried solving this with escape character, but that doesn't work. Would following code work by any chance?
String compare = "sin()";
string = string.replaceAll(compare, "");
replaceAll's first parameter is a regular expression, of which ( and ) are special characters. You would instead need to use
string = string.replaceAll("sin\\(\\)", "");
Note the use of \\ - \ is actually a special character in Java strings, so you must first escape the \ by using \\.
String z = "sin() is equal sin()";
Log.d("TEST",z);
z = z.replaceAll("sin\\(\\)", "");
Log.d("TEST",z);
Gives following output:
sin() is equal sin()
is equal
You need to separate your ( and ) because its a special charaters
So you need to use "\\"
example:
string = string.replaceAll("sin\\(\\)", "");
I am trying to remove double quotes before square bracket like "[
and I am using following code to do it but it says illegal escape charecter.
str = str.replace("\[","[");
I want to remove only double quotes ie " which is only before square bracket ie [. Please guide me.
You can use:
str = str.replaceAll("\"\\[", "[");
Both replace() and replaceAll() do the job. Using replace, you don't have to cope with regular expressions. Don't get confused by the name. In fact replace replaces all occurrences, not just the first.
str = str.replace("\"[", "[");
This question already has answers here:
Android split not working correctly
(2 answers)
Closed 7 years ago.
in my android app, i would like to split an array value into another array.
i have an Array with the name ArrayA.
log of ArrayA[0]:
Peter|Mustermann
now i would like to split Peter and Mustermann, i try this:
String [] ArrayB = ArrayA[0].split("|");
But the Log of ArrayB[0] and ArrayB[1] will not be:
Peter
And
Mustermann
it will be:
P
And
nothing
Any ideas ? :(
The public String[] split(String regex) works with a regular expression.
In a regular expression | is a reserved character, so try to escape it using
String [] ArrayB = ArrayA[0].split("\\|");
See here for more information about other reserved characters: http://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html#sum
And see here for a compilable sample: http://ideone.com/fjXNoJ
You'll have use it as follows:
String [] ArrayB = Array[0].trim().split("\\|");
As '\' is a special character also (along with |), two backslashes in a string literal will mean one backslash in the actual String, which in turn will represent a regular expression that matches a single backslash character.
Just use a single quote
String [] ArrayB = ArrayA[0].split('|');
String s1=s.replace('"', '\"');
here i want to replace " with \"
Try String s1 = s.replace("\"", "\\\"");
Explanation:
When referencing a quote or backslash in a string, i.e. anything inside double quotes, a \ is required to state that you want the quote to appear within the quotes, not end the quotes. Does this make sense?
For example, you would write String message = "She said \"Hello\" the other day.", so that the backslashes represent that the quotes don't actually end the whole string, but are rather to be part of the string.
String s1=s.replace("\"", "\\\"");
It will replace all " by \".