CODEWITHSUNDEEP
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Madamespring
Madamespring

Reputation: 35

How to subtract one row from others in r?

i have a dataframe with many columns and rows, i need to for each column subtract the first row from other rows. 

C1 C2 C3
3  7   9
4  9   4
7  6  11
9  4   8

Upvotes: 1

Views: 5688

Answers (2)

A5C1D2H2I1M1N2O1R2T1
A5C1D2H2I1M1N2O1R2T1

Reputation: 193687

You can actually subtract fairly directly, but you need to provide the first row as a list:

mydf - as.list(mydf[1, ])
#   C1 C2 C3
# 1  0  0  0
# 2  1  2 -5
# 3  4 -1  2
# 4  6 -3 -1

## OR
mydf - c(mydf[1, ])

Upvotes: 12

akrun
akrun

Reputation: 887951

We can replicate the first row to create the lengths same and then do the difference.

 df1-df1[1,][col(df1)]
 #  C1 C2 C3
 #1  0  0  0
 #2  1  2 -5
 #3  4 -1  2
 #4  6 -3 -1

Or another option is transposing (t) the dataset, get the difference and transpose it again, which may be less efficient

t(t(df1)- unlist(df1[1,]))
#     C1 C2 C3
#[1,]  0  0  0
#[2,]  1  2 -5
#[3,]  4 -1  2
#[4,]  6 -3 -1

Upvotes: 2

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