You don't need a StringBuilder. The compiler will take care of that simple concatenation prior to the regex for you by using one.
Edit in response to comment below:
replaceAll() uses a Regular Expression (regex).
The regex (.) says "match any character, and give me a reference to it" . is a wildcard for any character, the parenthesis create the backreference. The $1 in the second argument says "Use backreference #1 from the match".
replaceAll() keeps running this expression over the whole string replacing each character with itself followed by a percent sign, building a new String which it then returns to you.
I have a 2.67 GHz Celeron processor, 1.21 GB of RAM on a x86 Windows XP Professional machine. My understanding is that the Android emulator should start fairly quickly on such a machine, but for me it does not. I have followed all instructions in setting up the IDE, SDKs, JDKs and such and have had some success in staring the emulator quickly but is very particulary. How can I, if possible, fix this problem?
String foo = "VWXYZ";
ReplyDeletefoo = "%" + foo.replaceAll("(.)","$1%");
System.out.println(foo);
Output:
%V%W%X%Y%Z%
You don't need a StringBuilder. The compiler will take care of that simple concatenation prior to the regex for you by using one.
Edit in response to comment below:
replaceAll() uses a Regular Expression (regex).
The regex (.) says "match any character, and give me a reference to it" . is a wildcard for any character, the parenthesis create the backreference. The $1 in the second argument says "Use backreference #1 from the match".
replaceAll() keeps running this expression over the whole string replacing each character with itself followed by a percent sign, building a new String which it then returns to you.
string str="AA";
ReplyDeleteStringBuilder sb = new StringBuilder();
for(int i = 0; i < str.length(); s++)
{
sb.append("%");
sb.append(str.charAt(i));
}
sb.append("%");
This is the simpliest way to do that.
Try something like this:
ReplyDeleteString test = "ABC";
StringBuilder builder = new StringBuilder("");
builder.append("%");
for (char achar : test.toCharArray()) {
builder.append(achar);
builder.append("%");
}
System.out.println(builder.toString());
public static String escape(String s) {
ReplyDeleteStringBuilder buf = new StringBuilder();
boolean wasLetter = false;
for (char c: s.toCharArray()) {
boolean isLetter = Character.isLetter(c);
if (isLetter && !wasLetter) {
buf.append('%');
}
buf.append(c);
if (isLetter) {
buf.append('%');
}
wasLetter = isLetter;
}
return buf.toString();
}
StringBuilder sb = new StringBuilder("AAAAAAA");
ReplyDeletefor(int i = sb.length(); i >= 0; i--)
{
sb.insert(i, '%');
}
You may see this.
ReplyDeleteString s="AAAA";
StringBuilder builder = new StringBuilder();
char[] ch=s.toCharArray();
for(int i=0;i<ch.length;i++)
{
builder.append("%"+ch[i]);
}
builder.append("%");
System.out.println(builder.toString());
Output
%A%A%A%A%