Execution time for seq_along(x) versus 1:length(x)

A little advantage for seq_along():

l> sibrary(embryogrowth)
> system.time(for (i in 1:100000) seq_along(NestsResult))
utilisateur     système      écoulé
      0.117       0.012       0.131
> system.time(for (i in 1:100000) 1:length(NestsResult))
utilisateur     système      écoulé
      0.143       0.005       0.148

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