java - Streamtokenizer to read very large numbers? -


i have take input containing large numbers of order 10^9 in java. how handle inputs fast? since streamtokenizer.nval gives double, how can read larger values??

before parsing, reset tokenizer syntax table , initialize recognize numbers words:

streamtokenizer tokenizer = new streamtokenizer(r); tokenizer.resetsyntax();  tokenizer.whitespacechars(0, 32);  tokenizer.wordchars('0', '9'); tokenizer.wordchars('-', '.'); tokenizer.wordchars('+', '+'); tokenizer.wordchars('a', 'z'); tokenizer.wordchars('a', 'z'); tokenizer.wordchars(0xa0, 0xff); // not needed here. */ tokenizer.slashslashcomments(true); tokenizer.slashstarcomments(true);  tokenizer.quotechar('"'); tokenizer.quotechar('\'');

then, when encountering word, check whether parseable number (a bit crude here, shows general idea):

... case streamtokenizer.tt_word:   if ("true".equals(tokenizer.sval)) {     result = boolean.true;   } else if ("false".equals(tokenizer.sval)) {     result = boolean.false;   } else if ("null".equals(tokenizer.sval)) {     result = null;   } else {     try {       result = long.parselong(tokenizer.sval);     } catch(numberformatexception e) {       try {         result = double.parsedouble(tokenizer.sval);       } catch (numberformatexception e2) {         throw new illegalstateexception(            "unexpected token: " + tokenizer.tostring());       }    }  }  tokenizer.nexttoken();  break;

whether works depends on use case: if want parse expressions (and not json in case), don't want set + or - word characters, general idea should still work treating them unary operators , detecting constants @ later stage.


Comments

Post a Comment

Popular posts from this blog

java.util.scanner - How to read and add only numbers to array from a text file -

i'm learning java , have question regarding reading file want read numbers file contains strings well. here example of file: 66.56 "3 java 3-43 5-42 2.1 1 and here coding: public class test { public static void main (string [] args){ if (0 < args.length) { file x = new file(args[0]); try{ scanner in = new scanner( new fileinputstream(x)); arraylist<double> test = new arraylist<>(); while(in.hasnext()){ if(in.hasnextdouble()){ double f=in.nextdouble(); test.add(f);} else {in.next();} } catch(ioexception e) { system.err.println("exception during reading: " + e); } } my problem add 66.56,2.1 , 1 doesn't add 3 after "3 or ignores 3-43 , 5-42 can tell me how skip strings , add doubles here? thanks all said 3 ie; "3, 3-43 , 4-42 strings either u read string , split , check number @ " , - or put in space between characters , integers. jvm after compilation tre...
Read more

rewrite - Trouble with Wordpress multiple custom querystrings -

i'm working on adding multiple querystring , doesn't seem work. i've found codes seems work others might i'm missing something. i want like: http://mydomain.com/board/?getyear=2013&getsometext2=sometext to http://mydomain.com/board/2013/sometext/ i added code below functions.php file. doesn't seem work should though. this works. echoing querystring gets both variable without problem. http://mydomain.com/board/2013/sometext/ but doesn't. tested querystring vis isset() seems nothing being set/get http://mydomain.com/board/2013/ function add_query_vars($vars) { $vars[] = "getyear"; $vars[] = "getsometext2"; return $vars; } add_filter('query_vars', 'add_query_vars'); function add_rewrite_rules($arules) { $anewrules = array('board/([^/]+)/([^/]+)/?$' => 'index.php?pagename=board&getyear=$matches[1]&getsometext2=$matches[2]'); $arules = $a...
Read more