Analysing entire dataframes instead of separate subsets in r [closed] - r

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Closed 9 years ago.
I have code that analyses Gforces in movement, that returns to me a plot of GForces over time. The script works for subsets of the data (categorized by ID) and I don't have a clue how to make it compatible for analyzing the entire dataframe at once, returning to me the results in a faceted graph (with ggplot for instance). Does anyone know how to do this or am i doomed to analyse my data by one ID at a time?
The code is:
#Subset by ID
number1 <-subset(positions,subset=(ID==1))
head(number1)
A <- numeric()
Al <- numeric()
Radius <- numeric()
GForce <- numeric()
D12 <- numeric()
D13 <- numeric()
D23 <- numeric()
Proportion <- numeric()
Proportion_sel <- numeric()
nr<-length(number1$Timestamp)
for(i in 3:nr){
D12[i] <- sqrt((positions$X[i-2]-positions$X[i-1])^2 + (positions$Y[i-2]-positions$Y[i-1])^2)
D23[i] <- sqrt((positions$X[i-1]-positions$X[i])^2 + (positions$Y[i-1]-positions$Y[i])^2)
D13[i] <- sqrt((positions$X[i-2]-positions$X[i])^2 + (positions$Y[i-2]-positions$Y[i])^2)
if (D13[i]>0) {
if ((((D12[i]^2+D13[i]^2-D23[i]^2)^2)/(4*(D13[i]^2))) > D12[i]^2) {
A[i] <- 0
Radius[i] <- 0
GForce[i] <- 0
}
else {
A[i] <- sqrt(D12[i]^2-(((D12[i]^2+D13[i]^2-D23[i]^2)^2)/(4*(D13[i]^2))))
Radius[i] <- ((0.5*D13[i])^2+(A[i])^2)/(2*A[i])
GForce[i] <- ((D12[i]+D23[i])/2)^2/Radius[i]
}
}
else {
A[i] <- 0
Radius[i] <- 0
GForce[i] <- 0
}
}
# GForce plot over Time
plot(number1$Timestamp,GForce)
This returns to me:
- a plot of Gforces over time
The problem seems to arise with finding a way to return the GForce per ID and return them as an additional column to the original dataframe. When this would be possible, it would also be easy to plot per ID using ggplot but I don't know how to accomplish this..
Data (simplified):
dput(positions)
structure(list(ID = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L
), Timestamp = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L,
12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 23L, 24L,
25L, 26L, 27L, 28L, 29L, 30L, 31L, 32L, 33L, 34L, 35L, 36L, 37L,
38L, 39L, 40L, 41L, 42L, 43L, 44L, 45L, 1L, 2L, 3L, 4L, 5L, 6L,
7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L,
20L, 21L, 22L, 23L, 24L, 25L, 26L, 27L, 28L, 29L, 30L, 31L, 32L,
33L, 34L, 35L, 36L, 37L, 38L, 39L, 40L, 41L, 42L, 43L, 44L, 45L
), X = c(-34.126, -34.087, -34.047, -34.01, -33.983, -33.973,
-33.985, -34.019, -34.07, -34.13, -34.188, -34.237, -34.273,
-34.295, -34.305, -34.307, -34.305, -34.301, -34.299, -34.297,
-34.296, -34.29, -34.272, -34.235, -34.178, -34.107, -34.034,
-33.967, -33.91, -33.865, -33.832, -33.81, -33.799, -33.8, -33.814,
-33.841, -33.878, -33.923, -33.975, -34.033, -34.098, -34.17,
-34.243, -34.311, -34.366, -33.691, -33.646, -33.598, -33.547,
-33.497, -33.452, -33.414, -33.383, -33.357, -33.331, -33.302,
-33.268, -33.234, -33.203, -33.179, -33.163, -33.154, -33.145,
-33.132, -33.111, -33.081, -33.041, -32.993, -32.937, -32.873,
-32.807, -32.74, -32.676, -32.611, -32.543, -32.468, -32.384,
-32.293, -32.199, -32.109, -32.029, -31.959, -31.899, -31.846,
-31.796, -31.749, -31.704, -31.659, -31.612, -31.561), Y = c(3.393,
3.396, 3.398, 3.402, 3.408, 3.419, 3.434, 3.452, 3.471, 3.489,
3.506, 3.518, 3.525, 3.526, 3.523, 3.518, 3.513, 3.511, 3.511,
3.513, 3.516, 3.517, 3.51, 3.494, 3.467, 3.434, 3.402, 3.376,
3.358, 3.348, 3.343, 3.343, 3.346, 3.351, 3.36, 3.373, 3.39,
3.408, 3.43, 3.453, 3.479, 3.506, 3.532, 3.555, 3.57, 6.684,
6.757, 6.823, 6.887, 6.953, 7.024, 7.099, 7.174, 7.245, 7.307,
7.363, 7.414, 7.466, 7.52, 7.579, 7.643, 7.71, 7.781, 7.853,
7.923, 7.988, 8.047, 8.098, 8.139, 8.173, 8.202, 8.228, 8.251,
8.27, 8.285, 8.298, 8.314, 8.337, 8.372, 8.423, 8.487, 8.558,
8.628, 8.688, 8.735, 8.768, 8.792, 8.814, 8.843, 8.881)), .Names = c("ID",
"Timestamp", "X", "Y"), row.names = c(NA, 90L), class = "data.frame")

Answer 1

I join #Arun, You need to explain what are you doing. The code is not really helpful, specially if is not well written and have some errors.
That's said , if I look in you code , you do a procees by ID. One idea is to put your code in a function and call it for each ID using lapply.
You create 3 plots by ID, So you can create a matrix layout , where you plot the 3 plots in each row.
ids <- unique(positions$ID)
layout(matrix(1:(length(ids)*3),ncol=3,byrow=TRUE))
Then you call your process for each ID, for example:
lapply(ids,function(myID){
number1 <-subset(positions,subset=(ID==myID))
.....
# GForce calculation
plot(number1$Timestamp,GForce) ## I change one line
...
sum(GForce[3:max])
})