Replacing row data in column

Question

The data set i am using treat missing value as -99 and now I need to replace all these -99 to the number in same row but different column.

Here is the example

V1   V2    V3  V4       V5            V6        V7
1   1958    3 1958.208 315.71       315.71    314.62    -1
2   1958    4 1958.292 317.45       317.45    315.29    -1
3   1958    5 1958.375 317.50       317.50    314.71    -1
4   1958    6 1958.458 **-99.99**   *317.10*  314.85    -1

I want to replace (V5, 4) with (V6, 4).

There are several missing data in V5 and we want to replace with the same row in V6.

How to achieve this?

You can specify na.string = -99 when you read the data in using read.table() and that will make `R recognize them as a missing value — mnel
– mnel, Commented Sep 18, 2012 at 4:42
Thanks but i want to replace by 317.10 the same row in column V6. Do you now how to replace that? — user1489975
– user1489975, Commented Sep 18, 2012 at 5:03

mnel · Accepted Answer · 2012-09-18 05:07:36Z

2

It would be more sensible to specify the NA values when you read in your data.

You can do this by specifying the na.string argument in read.table() (or some variant of such).

With your specific data, it is unclear whether you have a defined scheme (as in always replace with the value in the next column), but for replacing 'missing' values in column V5 with their respective values in V6 and assuming your data is called DF

 DF <- within(DF, V5 <- replace(V5, V5 == -99.99, V6[V5== -99.99])

would work.

If you have correctly specified the -99.99 as missing values (NA) then

DF <- within(DF, V5 <- replace(V5, is.na(V5), V6[is.na(V5)])

answered Sep 18, 2012 at 5:07

mnel

116k28 gold badges269 silver badges255 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

IRTFM Over a year ago

Using "==" with non-integer values is rather risky.

mnel Over a year ago

True. If the op reads the missing values correctly, it would avoided.

Collectives™ on Stack Overflow

Replacing row data in column

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related