Binary Run-Length Encoding

Question

Overview

Run-length encoding — sequences in which the same data value occurs in many consecutive data elements are stored as a single data value and count

When using run-length encoding:

Input:  ABBBCCACB
Output: 1A3B2C1A1C1B

This sample has an output that is larger than the input.

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Instead, it can be simplified for binary inputs by removing the data value in the result,

Input:  10001110101
Output: 1331111

which is significantly smaller. This works because, logically, if the there is a "next subset" then it must be of a different data value than the current subset. Since there are only two possible values (1 and 0), you always know the "next" data value subset.

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Challenge

Implement binary run-length encoding demonstrated above.

• Take input through STDIN or suitable alternative.

• Output to STDOUT or suitable alternative.

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Examples

In:  101011101011000011
Out: 11113111242

In:  01001010001
Out: 11211131

In:  000000000
Out: 9

You may assume that no subsets will be longer than 9 characters (there won't be 10 adjacent zeroes).

Answer 1

Pyth - 5 bytes

hMrz8

Test Suite.

Answer 2

Ruby, 37 29 bytes

->s{s.gsub(/0+|1+/){$&.size}}

Test:

->s{s.gsub(/0+|1+/){$&.size}}["10001110101"]
=> "1331111"

Answer 3

Stuck, 5 bytes

soT]y

Takes a binary string as input and outputs an array.

Explanation

soT]y

s       get input string
 o      run-level encoding
  T     zip
   ]    flatten
    y   pops the data values off

Answer 4

CJam, 6 bytes

le`s2%

Try it here.

Answer 5

Haskell, 39 bytes

import Data.List
(show.length=<<).group

Unfortunately group is in Data.List, so I need the import.

Usage example: (show.length=<<).group $ "101011101011000011" -> "11113111242".