Cutting a string in Java

[Drenriza]

Hi guys.

I have the following 3 strings.


aaaaaaa <img class='avatar' alt='' src='http://path/x.png' /
bbbbbbbbbb </strong
cccc ccccc #6</li

How can i cut this to


aaaaaaa
bbbbbbbbbb
6


How can you say, print everything before the first < in the first two and print the first character after #

Thanks on advance.
Kind regards

[bird1500]

You mean JavaScript

[Drenriza]

You mean JavaScript

I mean Java :)

The output above have i gotten from saying


url = new URL("website (http://cogdev.net/blink/?act=home)");
dis = new DataInputStream((new BufferedInputStream(is = url.openStream())));

[Vaphell]

string.split( regex ) and then take proper element from the returned array? #1, #2: "<", #3: "#|<"

[lykeion]

String.split() is fine for splitting strings, but for HTML it's better to use a proper parser like jsoup, see http://jsoup.org

[Drenriza]

string.split( regex ) and then take proper element from the returned array? #1, #2: "<", #3: "#|<"

Yes i have tried the split command. But how do i get it to cut the characters infront of the delimiter and not after?

[Vaphell]

if you use regex '# OR <' result[1] will be the number alone

to illustrate the idea using awk (i don't know java, i have no clue how to write even 'hello world')

echo "cccc ccccc #6</li" | awk '{ str=$0; n=split(str, a, "<|#"); for( i=1; i<=n; i++) print i ":" a[i]; }'
1:cccc ccccc
2:6
3:/li

if you really have to get the the last char of the subpart, something like string[i].substr( string[i].length()-2, 1 )

[Drenriza]

String.split() is fine for splitting strings, but for HTML it's better to use a proper parser like jsoup, see http://jsoup.org

It sounds cleaver enough, but dunno how to proced with it.

The documentation (that i can find) is less then perfect :confused:

[Drenriza]

Anyone who can help me out?

Even tho vaphell comes with some suggestions, i cant seam to get it work as i want.

[Vaphell]

i don't even... o.O ;-)

my first java program ever

class test
{
public static void main(String args[])
{
String[] str = { "aaaaaaa <img class='avatar' alt='' src='http://path/x.png' /", "bbbbbbbbbb </strong", "cccc ccccc #6</li" };
String[] parts;

for( int n=0; n<str.length; n++ )
{
System.out.printf("string = %s\n", str[n] );
parts = str[n].split("<|#");
for( int i=0; i<parts.length; i++ )
System.out.printf( "parts[%d] = '%s'\n", i, parts[i] );
// assuming next-to-last element
System.out.printf( "result = '%s'\n", parts[parts.length-2] );
}
};
}


$ javac test.java
$ java test
string = aaaaaaa <img class='avatar' alt='' src='http://path/x.png' /
parts[0] = 'aaaaaaa '
parts[1] = 'img class='avatar' alt='' src='http://path/x.png' /'
result = 'aaaaaaa '
string = bbbbbbbbbb </strong
parts[0] = 'bbbbbbbbbb '
parts[1] = '/strong'
result = 'bbbbbbbbbb '
string = cccc ccccc #6</li
parts[0] = 'cccc ccccc '
parts[1] = '6'
parts[2] = '/li'
result = '6'


but i agree that this can work reliably only in simplest of cases and a proper parser may be required.

[ofnuts]

Hi guys.

I have the following 3 strings.


aaaaaaa <img class='avatar' alt='' src='http://path/x.png' /
bbbbbbbbbb </strong
cccc ccccc #6</liHow can i cut this to


aaaaaaa
bbbbbbbbbb
6
How can you say, print everything before the first < in the first two and print the first character after #

Thanks on advance.
Kind regards
String.split() is IMHO a bit simplistic here, you have better use a regular expression (in Java these are mostly covered by java.util.regex.Patten and java.util.regex.Matcher). (http://docs.oracle.com/javase/1.4.2/docs/api/java/util/regex/Pattern.html)


Come up with a regular expression that describes your expected string and use grouping parentheses for the parts you want to extract. This is the hard part, and requires a specification much less ambiguous than your question above.
Initialize a Pattern from it (this can be built once and reused for each match).
For each string you want to analyze, ask the pattern to create a Matcher from it.
Ask the matched if it matched, and if so, retrieve the groups from it.

[Drenriza]

i don't even... o.O ;-)

my first java program ever

class test
{
public static void main(String args[])
{
String[] str = { "aaaaaaa <img class='avatar' alt='' src='http://path/x.png' /", "bbbbbbbbbb </strong", "cccc ccccc #6</li" };
String[] parts;

for( int n=0; n<str.length; n++ )
{
System.out.printf("string = %s\n", str[n] );
parts = str[n].split("<|#");
for( int i=0; i<parts.length; i++ )
System.out.printf( "parts[%d] = '%s'\n", i, parts[i] );
// assuming next-to-last element
System.out.printf( "result = '%s'\n", parts[parts.length-2] );
}
};
}


$ javac test.java
$ java test
string = aaaaaaa <img class='avatar' alt='' src='http://path/x.png' /
parts[0] = 'aaaaaaa '
parts[1] = 'img class='avatar' alt='' src='http://path/x.png' /'
result = 'aaaaaaa '
string = bbbbbbbbbb </strong
parts[0] = 'bbbbbbbbbb '
parts[1] = '/strong'
result = 'bbbbbbbbbb '
string = cccc ccccc #6</li
parts[0] = 'cccc ccccc '
parts[1] = '6'
parts[2] = '/li'
result = '6'


but i agree that this can work reliably only in simplest of cases and a proper parser may be required.

Vaphell wouldn't you be kind enough to explain what your doing.

For example what does your %d and %s do.

[Drenriza]

String.split() is IMHO a bit simplistic here, you have better use a regular expression

If you have a good guide / book. Please dont hold back :)

[Vaphell]

it's a run-of-the-mill printf() function that works the same in C, bash, awk and tons of other languages. I noticed java has printf so i used it instead of googling for a kosher way of doing things in the language.
First arg is the format string where %X are placeholders filled with the subsequent args. %d is for numbers, %s is for strings

System.out.printf( "parts[%d] = '%s'\n", i, parts[i] );

http://en.wikipedia.org/wiki/Printf_format_string

[ofnuts]

If you have a good guide / book. Please dont hold back :)

http://www.amazon.com/Mastering-Regular-Expressions-Jeffrey-Friedl/dp/0596528124/ref=sr_1_1

Accept no substitutes.