R sorts a vector on its own accord

Question

df.sorted <- c(\"binned_walker1_1.grd\", \"binned_walker1_2.grd\", \"binned_walker1_3.grd\",
    \"binned_walker1_4.grd\", \"binned_walker1_5.grd\", \"binned_walk         


        

Answer 1

construct it as an ordered factor:

> df.new <- ordered(df.sorted,levels=df.sorted)
> order(df.new)
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 ...

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EDIT :

After @DWins comment, I want to add that it is even not nessecary to make it an ordered factor, just a factor is enough if you give the right order of levels :

>     df.new2 <- factor(df.sorted,levels=df.sorted)
>     order(df.new)
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 ...

The difference will be noticeable when you use those factors in a regression analysis, they can be treated differently. The advantage of ordered factors is that they let you use comparison operators as < and >. This makes life sometimes a lot easier.

> df.new2[5] < df.new2[10]
[1] NA
Warning message:
In Ops.factor(df.new[5], df.new[10]) : < not meaningful for factors

> df.new[5] < df.new[10]
[1] TRUE