"Concatenate" vs. "merge" vs. "join" in scientific text
I wonder what the difference is between concatenate, merge and join from the lexical point of view.
These words are often used in scientific or programming text. It seems to me that different authors use any of them with slightly different meaning. How should they be used from the language point of view?
Solution 1:
To me, concatenate refers to the very specific operation of appending things in order, specifically abstract things. Words and ideas can be concatenated, but things in the real world are usually not said to be concatenated. The word is mostly used in programming discussion and other discussion involving strings.
Merge usually implies mixing; if two companies, two ideas, or two galaxies are merged, they are implied to form one new entity in which the previous two are not distinguishable as wholes. It is more vague than concatenate.
Join can mean many things and it often depends on the context. If two organizations are joined, they may remain two organizations but under a larger name or cause or goal. Join seems to imply, sometimes, that there is something connecting two or more entities but those entities are still distinguishable. The word is a lot less specific on its own than the other two, though.
Solution 2:
Consider the lists:
List A
alpha
bravo
charlie
echo
golf
List B
bravo
foxtrot
golf
hotel
Concatenation would be appending one list to the end of the other, so concatenating List A to List B would result in:
Concatenation
alpha
bravo
charlie
echo
golf
bravo
foxtrot
golf
hotel
Merging refers to combining the two lists together, preserving their order. Depending on the context it could keep only the unique records or preserve them.
Merge
alpha
bravo
charlie
echo
foxtrot
golf
hotel
Joining refers to keeping only the records common to both lists.
Join
bravo
golf
Solution 3:
- join: link; connect:
- concatenate: link (things) together in a chain or series:
- merge: combine or cause to combine to form a single entity:
- combine: join or merge to form a single unit or substance
- connect: bring together or into contact so that a real or notional link is established:
In other words, join and concatenate link or connect things to form a chain or series. Merge and combine unite things to form a new entity where its original parts are indistinct. A merge could coincidentally also be a join.
Solution 4:
I only know concatenate from scientific contexts and I don’t think the word enjoys much day-to-day usage (though I’m happy to be corrected here).
Merge and, especially, join are more common in daily usage. The difference between them, to my mind, is that things that merge generally lose their individual identity, whereas things that join do not (or need not). For instance, if two rivers merge, it suggests that a new river is formed, but if one river joins another, then it suggests that one is a tributary and the other retains its identity. Or consider herds: if two herds merge, then you can’t recover the original herds any more (maybe wildebeest do this); but herds of elephants may join together for a period then separate into their original groups.