uniq for unsorted data

awk '!_[$0]++{print}'

By: dz
2009-02-06 09:52:35

What Others Think

Maybe I'm missing something, but: a - I can't see how this works b - it doesn't seem to work ...Create 3 line file test.txt: '$ cat test.txt: 1 3 2 '$ awk '!_[$0]++{print}' test.txt 1 3 2 Am I being thick?
g__j · 623 weeks and 5 days ago
How about: sort -u
systemj · 623 weeks and 5 days ago
g__j: it does 'uniq' but without requiring (or doing) sorting; cat >test 1 3 2 3 1 awk '!_[$0]++{print}' < test 1 3 2 You can actually shorten it to: awk '!_[$0]++'
porges · 623 weeks and 5 days ago
>>How about: >>sort -u I think this has several advantages: * No need for the overhead of a sort * Can be embedded in an awk conditional statement. for example: printf "a\nb\na\nc\na\nc\n" | awk '{if(!_[$0]++){print}}' * Can be inverted. To show only values that have been seen before. For example: printf "a\nb\na\nc\na\nc\n" | awk '{if(_[$0]++){print}}'
unixmonkey3280 · 608 weeks and 1 day ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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