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How to compare & replace x10 variable with a String containing x10 inside

I've been trying to do:
double x10 = 2.4;
String str = "The value of a variable is x10";
int c = 0;
while(c<str.length) #Here digit means a valid Number
if(str.charAt[c]==digit && str.charAt[c+1]==digit){
str.charAt[c] = Double.toString(x10);
}
Desired Output:
The value of a variable is 2.4
Problem:
The problem is that it doesn't seems to be comparing 10 in a String,
so that it can replace the x10 in the string with the value of variable x10.
Is there any other way to achieve the desired goal???
it works fine with variable x(1-9) but when it exceeds x10 & greater it stucks.
Didn't found anything relevant to my problem.
Any help would be highly encouraged!

I assume you are in C#. You can use the Regex.Replace variant that takes a MatchEvaluator delegate. Assuming your values are in double[] values and that they substitutions are one off in value (e.g. "x1" corresponds to values[0]), you do:
var ans = Regex.Replace(str, #"x(\d+)", m => values[Convert.ToInt32(m.Groups[1].Value)-1].ToString());

After so many tries, in order to achieve the desired output. I finally figured it out the way to solve it.
String str = "x12",str2 = "x1";
if(str2.matches("x[0-9]{1}")==true){
int var = Integer.parseInt(str.substring(1,2));
System.out.println(var);
}else{
System.out.println("Not Found!");
}if(str.matches("x[0-9]{2}")==true){
int var = Integer.parseInt(str.substring(1,2));
int var2 = Integer.parseInt(str.substring(2,3));
var = var * 10 + var2;
System.out.println(var);
}else{
System.out.println("Not Found!");
}

Converting EditText Value to int

My program sets a numeric value to an editText field..I am trying to convert the edittext values to an integer..I have failed in all the attempts i have tried..Here is how the editText field receives the value:
public void onDataChange(DataSnapshot snapshot) {
for (DataSnapshot postSnapshot : snapshot.getChildren()) {
DogExpenditure dogExpenditure = postSnapshot.getValue(DogExpenditure.class);
totalAmount[0] += dogExpenditure.getAmount();
textView3.setText(Integer.toString(totalAmount[0] ));
}
}
textView3.setText(Integer.toString(totalAmount[0] I am doing this because the totalAmount[0] cannot be accessed anywhere else other than inside that program so i decided to pull it from the editText(not sure about this) though i havent succeeded. i get java.lang.NumberFormatException: Invalid int: "" error:
Here is how i tried :
String diff = String.valueOf(textView3.getText());
Integer x = Integer.valueOf(diff);
String saley = String.valueOf(textView5.getText());
Integer v = Integer.valueOf(saley);
NB: the textView5 and textView5 are both EditText fields..

A NumberFormatException tell you the String is not a number.
Here, the String is empty so this can't be parse. A solution would be to check for that specific value, like Jesse Hoobergs answer.
But this will not prevent an exception if I input foobar. So the safer solution is to catch the exception. I let you find the correct solution to manager the value if this is not a numerical value.
Integer number;
try{
number = Integer.valueOf(s);
} catch(NumberFormatException nfe){
number = null; //Just an example of default value
// If you don't manage it with a default value, you need to throw an exception to stop here.
}
...

At startup, the value of the editText seems to be an empty string ("").
I think you can best check for empty strings or make sure the initial value isn't an empty string.
String diff = String.valueOf(textView3.getText());
Integer x = null;
if(!diff.trim().isEmpty())
x = Integer.valueOf(diff);

an example that may help you
boolean validInput = true;
String theString = String.valueOf(textView3.getText());
if (!theString.isEmpty()){ // if there is an input
for(int i = 0; i < theString.length(); i++){ // check for any non-digit
char c = theString.charAt(i);
if((c<48 || c>57)){ // if any non-digit found (ASCII chars values for [0-9] are [48-57]
validInput=false;
}
}
}
else {validInput=false;}
if (validInput){// if the input consists of integers only and it's not empty
int x = Integer.parseInt(theString); // it's safe, take the input
// do some work
}

Ok i found out a better way to deal with this..On startup the values are null..so i created another method that handles the edittext fields with a button click after the activity has been initialised..and it works..
private void diffe() {
String theString = String.valueOf(textView3.getText().toString().trim());
String theStringe = String.valueOf(textView5.getText().toString().trim());
int e = Integer.valueOf(theString);
int s = Integer.valueOf(theStringe);
int p = s - e ;
textView2.setText(Integer.toString(p));
}

how to parse integer from a long string

I want to parse two values from a string in android studio.
I cannot change the data type from web so I need to parse an Intt.The string that I receive from web is
5am-10am.
How can I get these values i.e. 5 and 10 from the string "5am-10am".
Thanks in advance for help.

its work only this kind of format "Xam-Yam".
String value="5am-10am";
value.replace("am","");
value.replace("pm","");//if your string have pm means add this line
String[] splited = value.split("-");
//splited[0]=5
//splited[1]=10

Here is the trick you should use:-
String timeValue="5am-10am";
String[] timeArray = value.split("-");
// timeArray [0] == "5am";
// timeArray [1] == "10am";
timeArray [0].replace("am","");
// timeArray [0] == "5";// what u needed
timeArray [1].replace("am","");
// timeArray [1] == "10"; // what u needed

So, the code below shows step by step how to parse the format you are given. I also added in the steps to use the newly parsed Strings as ints so you can perform arithmetic on them. Hope this helps.
`/*Get the input*/
String input = "5am-10am"; //Get the input
/*Separate the first number from the second number*/
String[] values = input.split("-"); //Returns 'values[5am, 10am]'
/*Not the best code -- but clearly shows what to do*/
values[0] = values[0].replaceAll("am", "");
values[0] = values[0].replaceAll("pm", "");
values[1] = values[1].replaceAll("am", "");
values[1] = values[1].replaceAll("pm", "");
/*Allows you to now use the string as an integer*/
int value1 = Integer.parseInt(values[0]);
int value2 = Integer.parseInt(values[1]);
/*To show it works*/
int answer = value1 + value2;
System.out.println(answer); //Outputs: '15'`

I will use some regex to remove the other String and leave only the numeric data. sample code below:
public static void main(String args[]) {
String sampleStr = "5am-10pm";
String[] strArr = sampleStr.split("-"); // I will split first the two by '-' symbol.
for(String strTemp : strArr) {
strTemp = strTemp.replaceAll("\\D+",""); // I will use this regex to remove all the string leaving only numbers.
int number = Integer.parseInt(strTemp);
System.out.println(number);
}
}
The advantages of this is you don't need to specifically remove "am" or "pm" because all of the other character will be remove and the numbers will only be left.

I think that this way can be the faster. Please consider that the regex doesn't validates so it will parse values as "30am-30pm" for example. Validation comes apart.
final String[] result = "5am-10pm".replaceAll("(\\d)[pa]m", "$1").split("-");
System.out.println(result[0]); // -- 5
System.out.println(result[1]); // -- 10

Java: Get Float and String value from a String

I have a string, such as "4.25GB"
I'd like to get the floating part "4.25"
And get the string part "GB"
How to get the two values respectively in Java.
Thanks.

Try
String s = "4.25GB"
Float value = Float.valueOf(s.replaceAll("[^\\d.]", "")); // remove all non-numeric symbols
String f = s.replaceAll("[0-9]",""); // remove all numbers

To get Number Part: String numberPart = "4.25GB".replaceAll("[^0-9.]", "");
To get String part: String stringPart = "4.25GB".replaceAll("[^A-Za-z]", "");

Use String.replaceAll to first replace all non-digits and dot with "" to get the number then otherwise

You can write a function that will be similar to C# int.TryParse method, and use it in loop on your string, it will only work if you alwayes have a (NUM)(STRING) formation :
boolean tryParse(String value)
{
try
{
Integer.parseInt(value);
return true;
} catch(NumberFormatException e)
{
return false;
}
}

Use split/ substring concept. divide the string like below:
String Str = new String("4.25GB");
for (String retval: Str.split("G")){
System.out.println(retval);
}
//or u can use
String[] r = s.split("(?=\\p{Upper})");

You could use public String substring(int beginIndex, int endIndex)
String start = "4.25GB";
String numbers = start.substring(0,4);
String letters = start.substring(4,6);
Read more about substrings and how to use them here

Tested, works:
String str = "4.25GB" ;
String parts[] = str.split("(?i)(?<=\\d)(?=[a-z])|(?<=[a-z])(?=\\d)");
float number = Float.parseFloat(parts[0]) ;
String string = parts[1] ;
System.out.println(number); //4.25
System.out.println(string); //GB

You can use regular expression like this :
String s = "4.25GB";
String num = s.replaceAll("[^0-9.]", "");
System.out.println(num);
String str = s.replaceAll("[0-9.]", "");
System.out.println(str);
wish help you.

That depends on what "such as" means. Are all the strings in the format "x.xxGB"? If that's the case, then you can use substring(), as you know the exact number of 'float' chars and 'suffix' chars.
String theStr = "x.xxGB";
String numStr = theStr.substring(0, 4); // grab first 4 chars: "x.xx"
float numFloat = Float.parseFloat(numStr);
String suffix = theStr.substring(5); // or .substring(5, 7); if you know the exact length
If it's more variable than that, it gets more complicated. If you don't know the length of the leading number string, you'd have to check the first part as a valid float, with perhaps the easiest way to be gathering characters as the start and checking each succession as a valid float, with all the rest being considered a suffix. Maybe something like this (pseudocode-ish):
String theStr = "324.994SUFFIX"; // SomeArbitraryNumberAndSuffixString
String currNumStr = "";
Boolean bHaveFloat = true;
for (int i = 1; i < theStr.length(); i++){
String testStr = theStr.substring(0, i);
try{
float f = Float.parseFloat(testStr);
} catch (NumberFormatException nfe){
// handle the exception, printStackTrace, etc...
// failed so No longer have Valid String...
break;
}
currNumStr = testStr;
}
// currNumStr now has the valid numberString

Integer value of strings

How can I convert "1,000" (input obtained as a string) to an integer?

DecimalFormat df = new DecimalFormat("#,###");
int i = df.parse("1,000").intValue();
System.out.println(i);

Integer i = Integer.valueOf("1,000".replaceAll(",", ""));

String stringValue = "1,000";
String cleanedStringValue = stringValue.replace(',','');
int intValue = Integer.parseInt(cleanedStringValue);

ParseInt:
http://download.oracle.com/javase/1.4.2/docs/api/java/lang/Integer.html#parseInt%28java.lang.String%29

I'd take a look at this class: http://download.oracle.com/javase/1.4.2/docs/api/java/text/NumberFormat.html

String str ="1000";
Try this
int i = Integer.valueOf("1,000".replaceAll(",", ""));

Integer.parseInt("1000");
Prefer avoiding "magic numbers"
String num = "1000";
Integer.parseInt(num);

Use code like the following.
String str = "1000";
int result;
try {
result = Integer.parseInt(str);
} catch(NumberFormatException ex) {
System.err.println("That was not an integer");
}

Just replace all comma with empty string and then use convert.ToInt32();
string str = "1,000";
int num = Integer.parseInt(str.replace(",",""));

with a comma (,) in the the string you probably cannot do it.

Always prefer to use Long.ValueOf instead of new Long. Indeed, the new Long always result in a new object whereas Long.ValueOf allows to cache the values by the compiler. Thanks to the cache, you code will be faster to execute.