This 'applies' a function to each row to reverse columns if necessary:

x
V1 V2 V3 V4
1 G 0.892 A 0.108
2 G 0.883 T 0.117
3 T 0.500 C 0.500
4 A 0.617 G 0.383
5 G 0.925 A 0.075
6 A 0.967 G 0.033
7 C 0.883 T 0.117
8 C 0.633 T 0.367
9 G 0.950 A 0.050
10 C 0.742 G 0.258
11 G 0.875 T 0.125
12 T 0.167 C 0.833
13 C 0.792 A 0.208
str(x)
`data.frame': 13 obs. of 4 variables:
$ V1: chr "G" "G" "T" "A"
$ V2: num 0.892 0.883 0.5 0.617 0.925 0.967 0.883 0.633 0.95 0.742
$ V3: chr "A" "T" "C" "G"
$ V4: num 0.108 0.117 0.5 0.383 0.075 0.033 0.117 0.367 0.05 0.258

t(apply(x, 1, function(z){
+ if (z[1] < z[3]) return(z)
+ else return(z[c(3,4,1,2)])
+ }))
[,1] [,2] [,3] [,4]
1 "A" "0.108" "G" "0.892"
2 "G" "0.883" "T" "0.117"
3 "C" "0.500" "T" "0.500"
4 "A" "0.617" "G" "0.383"
5 "A" "0.075" "G" "0.925"
6 "A" "0.967" "G" "0.033"
7 "C" "0.883" "T" "0.117"
8 "C" "0.633" "T" "0.367"
9 "A" "0.050" "G" "0.950"
10 "C" "0.742" "G" "0.258"
11 "G" "0.875" "T" "0.125"
12 "C" "0.833" "T" "0.167"
13 "A" "0.208" "C" "0.792"
--

6/14/06, yohannes alazar <hannesalazar (AT) gmail (DOT) comwrote:

First I would really like to thank the mailing list for help I got in the
past, as a new to R I am really needing some support on hoe to code the
following problem.
>
>
>
I am trying to sort some data I have in a big file. The file has 4 columns
and 19000 rows. An example of it looks like this:-
>
>
>
G 0.892 A 0.108

G 0.883 T 0.117

T 0.5 C 0.5

A 0.617 G 0.383

G 0.925 A 0.075

A 0.967 G 0.033

C 0.883 T 0.117

C 0.633 T 0.367

G 0.95 A 0.05

C 0.742 G 0.258

G 0.875 T 0.125

T 0.167 C 0.833

C 0.792 A 0.208
>
>
>
Columns one and three are alphabets while three and four are their
corresponding values.

I wanted to sort this data so that my first and third columns are in
alphabetic order. For example in the first row the order is "G" then "A".
This is not in alphabetic order therefore we swap them along with their
values and it becomes:

A 0.108 G 0.892

Row two looks fine but row three needs the same rearrangement as row one.
And the final out put looks like:

A 0.108 G 0.892

G 0.883 T 0.117

C 0.5 T 0.5

A 0.617 G 0.383

A 0.075 G 0.925

A 0.967 G 0.033

C 0.883 T 0.117

C 0.633 T 0.367

A 0.05 G 0.95

C 0.742 G 0.258

G 0.875 T 0.125

C 0.833 T 0.167

A 0.208 C 0.792

Please some help with the relevant command names or a technique to code
this
task.

Thank you in advance

Regards Hannes

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