How to split a string between letters and digits or between digits and letters

Question

I m trying to work out a way of splitting up a string in java that follows a pattern like so   String a    123abc345def     The results from this should be the following   x 0     123   x 1     abc   x 2     345   x 3     def     However I m completely stumped as to how I can achieve this  Please can someone help me out  I have tried searching online for a similar problem  however it s very difficult to phrase it correctly in a search   Please note  The number of letters  amp  numbers may vary  e g  There could be a string like so  1234a5bcdef

User · Answer

You can try this   Pattern p   Pattern compile   a-z     d     Matcher m   p matcher  123abc345def    ArrayList lt String gt  allMatches   new ArrayList lt  gt     while  m find          allMatches add m group         The result  allMatches  will be     123    abc    345    def

User · Answer

I was doing this sort of thing for mission critical code  Like every fraction of a second counts because I need to process 180k entries in an unnoticeable amount of time  So I skipped the regex and split altogether and allowed for inline processing of each element  though adding them to an ArrayList lt String gt  would be fine   If you want to do this exact thing but need it to be something like 20x faster     void parseGroups String text        int last   0      int state   0      for  int i   0  s   text length    i  lt  s  i              switch  text charAt i                 case  0               case  1               case  2               case  3               case  4               case  5               case  6               case  7               case  8               case  9                   if  state    2                        processElement text substring last  i                        last   i                                    state   1                  break              default                  if  state    1                        processElement text substring last  i                        last   i                                    state   2                  break                      processElement text substring last

User · Answer

If you are looking for solution without using Java String functionality  i e  split  match  etc   then the following should help   List lt String gt  splitString String string            List lt String gt  list   new ArrayList lt String gt             String token               char curr          for  int e   0  e  lt  string length     1  e                  if  e    0                  curr   string charAt 0               else                   curr   string charAt --e                              if  isNumber curr                     while  e  lt  string length    amp  amp  isNumber string charAt e                          token    string charAt e                                       list add token                   token                     else                   while  e  lt  string length    amp  amp   isNumber string charAt e                          token    string charAt e                                       list add token                   token                                         return list         boolean isNumber char c            return c  gt    0   amp  amp  c  lt    9           This solution will split numbers and  words   where  words  are strings that don t contain numbers  However  if you like to have only  words  containing English letters then you can easily modify it by adding more conditions  like isNumber method call  depending on your requirements  for example you may wish to skip words that contain non English letters   Also note that the splitString method returns ArrayList which later can be converted to String array

User · Answer

You could try to split on    lt   D     d     lt   d     D   like   str split     lt    D      d     lt    d      D       It matches positions between a number and not-a-number  in any order        lt   D     d  - matches a position between a non-digit   D  and a digit   d     lt   d     D  - matches a position between a digit and a non-digit

User · Answer

Didn t use Java for ages  so just some pseudo code  that should help get you started  faster for me than looking up everything         string a    123abc345def    string   result   while a Length  gt  0           string part        if  part   a Match   d     Length     match digits                    else if  part   a Match   a     Length     match letters                    else            break     something invalid - neither digit nor letter       result append part         a   a SubStr part Length - 1      remove the part we ve found

User · Answer

Wouldn t this  d  D   do the job instead of the cumbersome      lt    D      d     lt    d      D

User · Answer

Use two different patterns   0-9   and  a-zA-Z   and split twice by each of them

User · Answer

How about   private List lt String gt  Parse String str        List lt String gt  output   new ArrayList lt String gt         Matcher match   Pattern compile   0-9    a-z    A-Z     matcher str       while  match find              output add match group               return output

[java] How to split a string between letters and digits (or between digits and letters)?

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