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For each row return the column name of the largest value
...amples using sample reproducible):
DF <- data.frame(V1=c(2,8,1),V2=c(7,3,5),V3=c(9,6,4))
colnames(DF)[apply(DF,1,which.max)]
[1] "V3" "V1" "V2"
A faster solution than using apply might be max.col:
colnames(DF)[max.col(DF,ties.method="first")]
#[1] "V3" "V1" "V2"
...where ties.method can be...
Applying a function to every row of a table using dplyr?
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edited Aug 6 '19 at 3:20
answered Jul 14 '14 at 0:20
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Does assignment with a comma work?
Why does aaa = 1,2,3 work and set the value of aaa to 1 ?
4 Answers
4
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“ValueError: zero length field name in format” error in Python 3.0,3.1,3.2
I'm trying learn Python (3 to be more specific) and I'm getting this error:
3 Answers
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Version of SQLite used in Android?
...database.sqlite package-level javadoc
Using the emulators:
adb shell sqlite3 --version
UPDATE: Since SDK 29 (emulator revision 8), the adb shell command gives:
/system/bin/sh: sqlite3: inaccessible or not found
Any ideas why? Issue tracker here.
SQLite 3.28.0 (window functions!):
30-11.0-R (Re...
How do I make a list of data frames?
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135
This isn't related to your question, but you want to use = and not <- within the function ca...
Base64 length calculation?
...log2(64) = 6).
Therefore 4 chars are used to represent 4 * 6 = 24 bits = 3 bytes.
So you need 4*(n/3) chars to represent n bytes, and this needs to be rounded up to a multiple of 4.
The number of unused padding chars resulting from the rounding up to a multiple of 4 will obviously be 0, 1, 2 or...
What does axis in pandas mean?
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399
It specifies the axis along which the means are computed. By default axis=0. This is consisten...
How do I use floating-point division in bash?
...d
– Nahuel Fouilleul
Oct 4 '12 at 7:32
4
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Assign multiple columns using := in data.table, by group
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This now works in v1.8.3 on R-Forge. Thanks for highlighting it!
x <- data.table(a = 1:3, b = 1:6)
f <- function(x) {list("hi", "hello")}
x[ , c("col1", "col2") := f(), by = a][]
# a b col1 col2
# 1: 1 1 hi hello
# 2: 2 2 hi hello
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