Here's a version using reduce:
(defn uniquify [items]
(first
(reduce (fn [[result count-map] item]
(let [n (inc (count-map item 0))]
[(conj result (str item "_" n))
(assoc count-map item n)]))
[[] {}]
items)))
Replace (str item "_" n) with (if (zero? n) item (str item "_" n) if you
don't want to append "_0" the first time you encounter a new string
On Friday, January 10, 2014 5:12:27 PM UTC+2, Alex Miller wrote:
>
> I would not use an atom. Think about it as doing a reduce while passing
> along a set of the names you've seen so far. You might also look at the
> implementation of "distinct" in clojure.core which is similar (you want to
> detect duplicates in the same way, but emit new names instead of omitting
> dupes).
>
>
> On Friday, January 10, 2014 8:59:10 AM UTC-6, Colin Yates wrote:
>>
>> I have a sequence of file names and I want to make them unique.
>> (uniquify ["a" "b" "c" "a"]) => ["a" "b" "c" "a_1"])
>>
>> This is what I have come up with, but surely there is a better way?
>>
>> What would you all do? Feedback welcome (including the word 'muppet' as
>> I am sure I have missed something simple) :)
>>
>> (defn uniquify
>> "Return a sequence, in the same order as s containing every element
>> of s. If s (which is presumed to be a string) occurs more than once
>> then every subsequent occurrence will be made unique.
>>
>> Items will be updated to include an incrementing numeric count using
>> the specified formatter function. The formatter function will be
>> given the name and the number and should return a combination of the
>> two.
>>
>> The set of unique s's in the returned sequence will be the count of
>> s's in s."
>> ([s] (uniquify s (fn [item duplicates] (str item "_" duplicates))))
>> ([s formatter]
>> (let [occurrences (atom {})
>> register-occurrence (fn [item]
>> (if (get @occurrences item)
>> (swap! (get @occurrences item) inc)
>> (swap! occurrences assoc item (atom
>> 1)))
>> @(get @occurrences item))
>> process (fn [item]
>> (let [duplicates (dec (register-occurrence item))]
>> (if (> duplicates 0)
>> (formatter item duplicates)
>> item)))
>> unique-s (map process s)]
>> unique-s)))
>>
>
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