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How to sort a dataframe by column(s) in R

I have a dataset that looks like this:

x y z 1. 1 0.2 1.1 1 1.5 1.2 1 3. 1. 2 8.1 1.1 2 1.0 1.2 2 0.6

What I would like is organise the dataset first as a function of x in increasing order then as a function of y such that

x y z 1. 1 0.2 1. 2 8.1 1.1 1 1.5 1.1 2 1. 1.2 1 3. 1.2 2 0.6

I know that apply, mapply, tapply, etc functions reorganise datasets but I must admit that I don't really understand the differences between them nor do I really understand how to apply which and when.

Thank you for your suggestions.

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You can order your data using the order function. There is no need for any apply family function.

Assuming your data is in a data.frame called df:

df[order(df$x, df$y), ] x y z 1 1.0 1 0.2 4 1.0 2 8.1 2 1.1 1 1.5 5 1.1 2 1.0 3 1.2 1 3.0 6 1.2 2 0.6

See ?order for more help.

On a side note: reshaping in general refers to changing the shape of a data.frame, e.g. converting it from wide to tall format. This is not what is required here.

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Very simple and efficient way to re-order my dataset. Thank you for the quick answers and suggestions for me to understand the differences between order(), reshape() etc...
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You can also use the arrange() function in plyr for this. Wrap the variables in desc() that you want to sort the other direction.

> library(plyr) > dat <- head(ChickWeight) > arrange(dat,weight,Time) weight Time Chick Diet 1 42 0 1 1 2 51 2 1 1 3 59 4 1 1 4 64 6 1 1 5 76 8 1 1 6 93 10 1 1

This is the fastest way to do this that's still readable, if speed matters in your application. Benchmarks here: How to sort a dataframe by column(s)?

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