CODEWITHSUNDEEP
regex
tolUene
tolUene

Reputation: 584

Regex to remove duplicate Characters completely (without leaving them behind)

I need a regex to remove duplicate characters from a string like so: abcdeafghid to bcefghi, removing a and d

I have no idea how I would go about this honestly. I can find a lot about removing duplicates, but they always leave behind one instance of the duplicated character.

The order of the characters at the end doesn't matter, but since I'm working with CJK languages it should support those. How would I go about this?

Upvotes: 0

Views: 376

Answers (2)

dawg
dawg

Reputation: 103744

You can do this one of two ways:

  1. build a string character by character for each unique character in the string
  2. use a regex to globally eliminate characters that exist more than once.

One line in Python:

>>> s='abcdeafghid'
>>> ''.join(c for c in s if s.count(c)==1) # only keep the ones that are singular
'bcefghi'

Or, filter out the ones that have more than one:

>>> s='abcdeafghid'
>>> filter(lambda c: s.count(c)==1, s)
'bcefghi'

In Perl you would create a hash with the counts of each character in the string then either delete the character with a regex or add in if the count is equal to 1:

my $s='abcdeafghid';
my %h;

$h{$_}++ foreach (split //, $s);    # count of all characters

while(my($k, $v) = each %h){ $s =~ s/$k//g if $v>1}

print $s;

Or,

my $s='abcdeafghid';
my %h;
my $new='';

$h{$_}++ foreach (split //, $s);

foreach (split //, $s) { $new.=$_ if $h{$_}==1}

print $new;

Upvotes: 2

AnalystCave.com
AnalystCave.com

Reputation: 4974

Irrelevant of you language you can use the pseudocode below:

Dictionary dict 
for i = 0 to Len(your_string)
  if Not(dict.Exits(your_string[i])) then 
     dict.Add(your_string[i],1)
  else
     dict[your_string[i]] += 1
  end if
Next i

int index = 0 
while 1
  if dict[your_string[index]] > 1 then
   your_string = replace(your_string, your_string[index],"")
   index = 0
  else 
   index +=1
   if index >= Len(your_string) then break
  end if  
end while

Upvotes: 1

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