Run a function in loop on a data frame of 3 values - r

Function given:
hmin = function (H,M,s) {
H - ((2*9.8*M)/1.5*s))
}
# Create a data frame to test One-at-A-Time sensitivity analysis
# Keep H and M constant, varying s
# H = 50, M = 70.5, s = 20 to 40
s1 <- numeric(length = 20)
s1 [1:21] <- c(20:40)
H1 <- c(rep(50,length(s1)))
M1 <- c(rep(70.5, length(s1)))
dataframe1 <- data.frame(H1,M1,s1)
Now with this data frame, How to run the hmin function over the variables in dataframe1 and store the output hmin in a vector to plot a barplot.
Tried using:
lapply(dataframe1, hmin (H1,M1,s1), dataframe1)
but it does not work.
Any help would be appreciated. Thank you.

My intended output is just to return the hmin values after running the data frame of variables using the function and saving it in a vector. How can I go about doing it?
Since your function is vectorized, do this:
result = hmin(H = dataframe1$H1, M = dataframe1$M1, s = dataframe1$s1)
# same thing, using the with() helper function to save typing
result = with(dataframe1, hmin(H = H1, M = M1, s = s1))

It is far more easily if you use dplyr
> library(dplyr)
> dataframe1 <- data.frame(H1,M1,s1)
> hmin <- function(H,M,s) {
+ H - ((2*9.8*M)/1.5*s)
+ }
> dataframe1 %>%
+ mutate(hminscores = hmin(H1, M1, s1))
H1 M1 s1 sensitivity
1 50 70.5 20 -18374.0
2 50 70.5 21 -19295.2
3 50 70.5 22 -20216.4
4 50 70.5 23 -21137.6
5 50 70.5 24 -22058.8
6 50 70.5 25 -22980.0
7 50 70.5 26 -23901.2
8 50 70.5 27 -24822.4
9 50 70.5 28 -25743.6
10 50 70.5 29 -26664.8
11 50 70.5 30 -27586.0
12 50 70.5 31 -28507.2
13 50 70.5 32 -29428.4
14 50 70.5 33 -30349.6
15 50 70.5 34 -31270.8
16 50 70.5 35 -32192.0
17 50 70.5 36 -33113.2
18 50 70.5 37 -34034.4
19 50 70.5 38 -34955.6
20 50 70.5 39 -35876.8
21 50 70.5 40 -36798.0
If you just want a vector, you can also use apply:
> hminscores <- apply(dataframe1, 1, function(x) {
+ hmin(x[1], x[2], x[3])
+ })
> hminscores
[1] -18374.0 -19295.2 -20216.4 -21137.6 -22058.8 -22980.0 -23901.2 -24822.4 -25743.6
[10] -26664.8 -27586.0 -28507.2 -29428.4 -30349.6 -31270.8 -32192.0 -33113.2 -34034.4
[19] -34955.6 -35876.8 -36798.0

Related

Apply loop for rollapply windows

I currently have a dataset with 50,000+ rows of data for which I need to find rolling sums. I have completed this using rollaply which has worked perfectly. I need to apply these rolling sums across a range of widths (600, 1200, 1800...6000) which I have done by cut and pasting each line of script and changing the width. While it works, I'd like to tidy my script but applying a loop, or similar, if possible so that once the rollapply function has completed it's first 'pass' at 600 width, it then completes the same with 1200 and so on. Example:
Var1 Var2 Var3
1 11 19
43 12 1
4 13 47
21 14 29
41 15 42
16 16 5
17 17 16
10 18 15
20 19 41
44 20 27
width_2 <- rollapply(x$Var1, FUN = sum, width = 2)
width_3 <- rollapply(x$Var1, FUN = sum, width = 3)
width_4 <- rollapply(x$Var1, FUN = sum, width = 4)
Is there a way to run widths 2, 3, then 4 in a simpler way rather than cut and paste, particularly when I have up to 10 widths, and then need to run this across other cols. Any help would be appreciated.
We can use lapply in base R
lst1 <- lapply(2:4, function(i) rollapply(x$Var1, FUN = sum, width = i))
names(lst1) <- paste0('width_', 2:4)
list2env(lst1, .GlobalEnv)
NOTE: It is not recommended to create multiple objects in the global environment. Instead, the list would be better
Or with a for loop
for(v in 2:4) {
assign(paste0('width_', v), rollapply(x$Var1, FUN = sum, width = v))
}
Create a function to do this for multiple dataset
f1 <- function(col1, i) {
rollapply(col1, FUN = sum, width = i)
}
lapply(x[c('Var1', 'Var2')], function(x) lapply(2:4, function(i)
f1(x, i)))
Instead of creating separate vectors in global environment probably you can add these as new columns in the already existing dataframe.
Note that rollaplly(..., FUN = sum) is same as rollsum.
library(dplyr)
library(zoo)
bind_cols(x, purrr::map_dfc(2:4,
~x %>% transmute(!!paste0('Var1_roll_', .x) := rollsumr(Var1, .x, fill = NA))))
# Var1 Var2 Var3 Var1_roll_2 Var1_roll_3 Var1_roll_4
#1 1 11 19 NA NA NA
#2 43 12 1 44 NA NA
#3 4 13 47 47 48 NA
#4 21 14 29 25 68 69
#5 41 15 42 62 66 109
#6 16 16 5 57 78 82
#7 17 17 16 33 74 95
#8 10 18 15 27 43 84
#9 20 19 41 30 47 63
#10 44 20 27 64 74 91
You can use seq to generate the variable window size.
seq(600, 6000, 600)
#[1] 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

How to resample and remodel n times by vectorization?

here's my for loop version of doing resample and remodel,
B <- 999
n <- nrow(butterfly)
estMat <- matrix(NA, B+1, 2)
estMat[B+1,] <- model$coef
for (i in 1:B) {
resample <- butterfly[sample(1:n, n, replace = TRUE),]
re.model <- lm(Hk ~ inv.alt, resample)
estMat[i,] <- re.model$coef
}
I tried to avoid for loop,
B <- 999
n <- nrow(butterfly)
resample <- replicate(B, butterfly[sample(1:n, replace = TRUE),], simplify = FALSE)
re.model <- lapply(resample, lm, formula = Hk ~ inv.alt)
re.model.coef <- sapply(re.model,coef)
estMat <- cbind(re.model.coef, model$coef)
It worked but didn't improve efficiency. Is there any approach I can do vectorization?
Sorry, not quite familiar with StackOverflow. Here's the dataset butterfly.
colony alt precip max.temp min.temp Hk
pd+ss 0.5 58 97 16 98
sb 0.8 20 92 32 36
wsb 0.57 28 98 26 72
jrc+jrh 0.55 28 98 26 67
sj 0.38 15 99 28 82
cr 0.93 21 99 28 72
mi 0.48 24 101 27 65
uo+lo 0.63 10 101 27 1
dp 1.5 19 99 23 40
pz 1.75 22 101 27 39
mc 2 58 100 18 9
hh 4.2 36 95 13 19
if 2.5 34 102 16 42
af 2 21 105 20 37
sl 6.5 40 83 0 16
gh 7.85 42 84 5 4
ep 8.95 57 79 -7 1
gl 10.5 50 81 -12 4
(Assuming butterfly$inv.alt <- 1/butterfly$alt)
You get the error because resample is not a list of resampled data.frames, which you can obtain with:
resample <- replicate(B, butterfly[sample(1:n, replace = TRUE),], simplify = FALSE)
The the following should work:
re.model <- lapply(resample, lm, formula = Hk ~ inv.alt)
To extract coefficients from a list of models, re.model$coef does work. The correct path to coefficients are: re.model[[1]]$coef, re.model[[2]]$coef, .... You can get all of them with the following code:
re.model.coef <- sapply(re.model, coef)
Then you can combined it with the observed coefficients:
estMat <- cbind(re.model.coef, model$coef)
In fact, you can put all of them into replicate:
re.model.coef <- replicate(B, {
bf.rs <- butterfly[sample(1:n, replace = TRUE),]
coef(lm(formula = Hk ~ inv.alt, data = bf.rs))
})
estMat <- cbind(re.model.coef, model$coef)

Function with a for loop to create a column with values 1:n conditioned by intervals matched by another column

I have a data frame like the following
my_df=data.frame(x=runif(100, min = 0,max = 60),
y=runif(100, min = 0,max = 60)) #x and y in cm
With this I need a new column with values from 1 to 36 that match x and y every 10 cm. For example, if 0<=x<=10 & 0<=y<=10, put 1, then if 10<=x<=20 & 0<=y<=10, put 2 and so on up to 6, then 0<=x<=10 & 10<=y<=20 starting with 7 up to 12, etc. I tried to make a function with an if repeating the interval for x 6 times, and increasing by 10 the interval for y every iteration. Here is the function
#my miscarried function 'zones'
>zones= function(x,y) {
i=vector(length = 6)
n=vector(length = 6)
z=vector(length = 36)
i[1]=0
z[1]=0
n[1]=1
for (t in 1:6) {
if (0<=x & x<10 & i[t]<=y & y<i[t]+10) { z[t] = n[t]} else
if (10<=x & x<20 & i[t]<=y & y<i[t]+10) {z[t]=n[t]+1} else
if (20<=x & x<30 & i[t]<=y & y<i[t]+10) {z[t]=n[t]+2} else
if (30<=x & x<40 & i[t]<=y & y<i[t]+10) {z[t]=n[t]+3} else
if (40<=x & x<50 & i[t]<=y & y<i[t]+10) {z[t]=n[t]+4}else
if (50<=x & x<=60 & i[t]<=y & y<i[t]+10) {z[t]=n[t]+5}
else {i[t+1]=i[t]+10
n[t+1]=n[t]+6}
}
return(z)
}
>xy$z=zones(x=xy$x,y=xy$y)
and I got
There were 31 warnings (use warnings() to see them)
>xy$z
[1] 0 0 0 0 25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Please,help me before I die alone!
I think think this does the trick.
a <- cut(my_df$x, (0:6) * 10)
b <- cut(my_df$y, (0:6) * 10)
z <- interaction(a, b)
levels(z)
[1] "(0,10].(0,10]" "(10,20].(0,10]" "(20,30].(0,10]" "(30,40].(0,10]"
[5] "(40,50].(0,10]" "(50,60].(0,10]" "(0,10].(10,20]" "(10,20].(10,20]"
[9] "(20,30].(10,20]" "(30,40].(10,20]" "(40,50].(10,20]" "(50,60].(10,20]"
[13] "(0,10].(20,30]" "(10,20].(20,30]" "(20,30].(20,30]" "(30,40].(20,30]"
[17] "(40,50].(20,30]" "(50,60].(20,30]" "(0,10].(30,40]" "(10,20].(30,40]"
[21] "(20,30].(30,40]" "(30,40].(30,40]" "(40,50].(30,40]" "(50,60].(30,40]"
[25] "(0,10].(40,50]" "(10,20].(40,50]" "(20,30].(40,50]" "(30,40].(40,50]"
[29] "(40,50].(40,50]" "(50,60].(40,50]" "(0,10].(50,60]" "(10,20].(50,60]"
[33] "(20,30].(50,60]" "(30,40].(50,60]" "(40,50].(50,60]" "(50,60].(50,60]"
If this types of levels aren't for your taste, then change as below:
levels(z) <- 1:36
Is this what you're after? The resulting numbers are in column res:
# Get bin index for x values and y values
my_df$bin1 <- as.numeric(cut(my_df$x, breaks = seq(0, max(my_df$x) + 10, by = 10)));
my_df$bin2 <- as.numeric(cut(my_df$y, breaks = seq(0, max(my_df$x) + 10, by = 10)));
# Multiply bin indices
my_df$res <- my_df$bin1 * my_df$bin2;
> head(my_df)
x y bin1 bin2 res
1 49.887499 47.302849 5 5 25
2 43.169773 50.931357 5 6 30
3 10.626466 43.673533 2 5 10
4 43.401454 3.397009 5 1 5
5 7.080386 22.870539 1 3 3
6 39.094724 24.672907 4 3 12
I've broken down the steps for illustration purposes; you probably don't want to keep the intermediate columns bin1 and bin2.
We probably need a table showing the relationship between x, y, and z. After that, we can define a function to do the join.
The solution is related and inspired by this post (R dplyr join by range or virtual column). You may also find other solutions are useful.
# Set seed for reproducibility
set.seed(1)
# Create example data frame
my_df <- data.frame(x=runif(100, min = 0,max = 60),
y=runif(100, min = 0,max = 60))
# Load the dplyr package
library(dplyr)
# Create a table to show the relationship between x, y, and z
r <- expand.grid(x_from = seq(0, 50, 10), y_from = seq(0, 50, 10)) %>%
mutate(x_to = x_from + 10, y_to = y_from + 10, z = 1:n())
# Define a function for dynamic join
dynamic_join <- function(d, r){
if (!("z" %in% colnames(d))){
d[["z"]] <- NA_integer_
}
d <- d %>%
mutate(z = ifelse(x >= r$x_from & x < r$x_to & y >= r$y_from & y < r$y_to,
r$z, z))
return(d)
}
re_dynamic_join <- function(d, r){
r_list <- split(r, r$z)
for (i in 1:length(r_list)){
d <- dynamic_join(d, r_list[[i]])
}
return(d)
}
# Apply the function
re_dynamic_join(my_df, r)
x y z
1 15.930520 39.2834357 20
2 22.327434 21.1918363 15
3 34.371202 16.2156088 10
4 54.492467 59.5610437 36
5 12.100916 38.0095959 20
6 53.903381 12.7924881 12
7 56.680516 7.7623409 6
8 39.647868 28.6870821 16
9 37.746843 55.4444682 34
10 3.707176 35.9256580 19
11 12.358474 58.5702417 32
12 10.593405 43.9075507 26
13 41.221371 21.4036147 17
14 23.046223 25.8884214 15
15 46.190485 8.8926936 5
16 29.861955 0.7846545 3
17 43.057110 42.9339640 29
18 59.514366 6.1910541 6
19 22.802111 26.7770609 15
20 46.646713 38.4060627 23
21 56.082314 59.5103172 36
22 12.728551 29.7356147 14
23 39.100426 29.0609715 16
24 7.533306 10.4065401 7
25 16.033240 45.2892567 26
26 23.166846 27.2337294 15
27 0.803420 30.6701870 19
28 22.943277 12.4527068 9
29 52.181451 13.7194886 12
30 20.420940 35.7427198 21
31 28.924807 34.4923319 21
32 35.973950 4.6238628 4
33 29.612478 2.1324348 3
34 11.173056 38.5677295 20
35 49.642399 55.7169120 35
36 40.108004 35.8855453 23
37 47.654392 33.6540449 23
38 6.476618 31.5616634 19
39 43.422657 59.1057134 35
40 24.676466 30.4585093 21
41 49.256778 40.9672847 29
42 38.823612 36.0924731 22
43 46.975966 14.3321207 11
44 33.182179 15.4899556 10
45 31.783175 43.7585774 28
46 47.361374 27.1542499 17
47 1.399872 10.5076061 7
48 28.633804 44.8018962 27
49 43.938824 6.2992584 5
50 41.563893 51.8726969 35
51 28.657177 36.8786983 21
52 51.672569 33.4295723 24
53 26.285826 19.7266391 9
54 14.687837 27.1878867 14
55 4.240743 30.0264584 19
56 5.967970 10.8519817 7
57 18.976302 31.7778362 20
58 31.118056 4.5165447 4
59 39.720305 16.6653560 10
60 24.409811 12.7619712 9
61 54.772555 17.0874289 12
62 17.616202 53.7056462 32
63 27.543944 26.7741194 15
64 19.943680 46.7990934 26
65 39.052228 52.8371421 34
66 15.481007 24.7874526 14
67 28.712715 3.8285088 3
68 45.978640 20.1292495 17
69 5.054815 43.4235568 25
70 52.519280 20.2569200 18
71 20.344376 37.8248473 21
72 50.366421 50.4368732 36
73 20.801009 51.3678999 33
74 20.026496 23.4815569 15
75 28.581075 22.8296331 15
76 53.531900 53.7267256 36
77 51.860368 38.6589458 24
78 23.399373 44.4647189 27
79 46.639242 36.3182068 23
80 57.637080 54.1848967 36
81 26.079569 17.6238093 9
82 42.750881 11.4756066 11
83 23.999662 53.1870566 33
84 19.521129 30.2003691 20
85 45.425229 52.6234526 35
86 12.161535 11.3516173 8
87 42.667273 45.4861831 29
88 7.301515 43.4699336 25
89 14.729311 56.6234891 32
90 8.598263 32.8587952 19
91 14.377765 42.7046321 26
92 3.536063 23.3343060 13
93 38.537296 6.0523876 4
94 52.576153 55.6381253 36
95 46.734881 16.9939500 11
96 47.838530 35.4343895 23
97 27.316467 6.6216363 3
98 24.605045 50.4304219 33
99 48.652215 19.0778211 11
100 36.295997 46.9710802 28

Extracting chunks from a matrix by columns

Say I have a matrix with 1000 columns. I want to create a new matrix with every other n columns from the original matrix, starting from column i.
So let say that n=3 and i=5, then the columns I need from the old matrix are 5,6,7,11,12,13,17,18,19 and so on.
Using two seq()s to create the start and stop bounds, then using a mapply() on those to build your true column index intervals. Then just normal bracket notation to extract from your matrix.
set.seed(1)
# using 67342343's test case
M <- matrix(runif(100^2), ncol = 100)
n <- 3
i <- 5
starts <- seq(i, ncol(M), n*2)
stops <- seq(i+(n-1), ncol(M), n*2)
col_index <- c(mapply(seq, starts, stops)) # thanks Jaap and Sotos
col_index
[1] 5 6 7 11 12 13 17 18 19 23 24 25 29 30 31 35 36 37 41 42 43 47 48 49 53 54 55 59 60 61 65 66 67 71 72 73 77 78
[39] 79 83 84 85 89 90 91 95 96 97
M[, col_index]
Another solution is based on the fact that R uses index recycling:
i <- 5; n <- 3
M <- matrix(runif(100^2), ncol = 100)
id <- seq(i, ncol(M), by = 1)[rep(c(TRUE, FALSE), each = n)]
M_sub <- M[, id]
I would write a function that determines the indices of the columns you want, and then call that function as needed.
col_indexes <- function(mat, start = 1, by = 1){
n <- ncol(mat)
inx <- seq(start, n, by = 2*by)
inx <- c(sapply(inx, function(i) i:(i + by -1)))
inx[inx <= n]
}
m <- matrix(0, nrow = 1, ncol = 20)
icol <- col_indexes(m, 5, 3)
icol
[1] 5 6 7 11 12 13 17 18 19
Here is a method using outer.
c(outer(5:7, seq(0L, 95L, 6L), "+"))
[1] 5 6 7 11 12 13 17 18 19 23 24 25 29 30 31 35 36 37 41 42 43 47 48 49 53
[26] 54 55 59 60 61 65 66 67 71 72 73 77 78 79 83 84 85 89 90 91 95 96 97
To generalize this, you could do
idx <- c(outer(seq(i, i + n), seq(0L, ncol(M) - i, 2 * n), "+"))
The idea is to construct the initial set of columns (5:7 or seq(i, i + n)), calculate the starting points for every subsequent set (seq(0L, 95L, 6L) or seq(0L, ncol(M) - i, 2 * n)) then use outer to calculate the sum of every combination of these two vectors.
you can subset the matrix using [ like M[, idx].

Outputting percentiles by filtering a data frame

Note that, as requested in the comments, that this question has been revised.
Consider the following example:
df <- data.frame(FILTER = rep(1:10, each = 10), VALUE = 1:100)
I would like to, for each value of FILTER, create a data frame which contains the 1st, 2nd, ..., 99th percentiles of VALUE. The final product should be
PERCENTILE df_1 df_2 ... df_10
1 [first percentiles]
2 [second percentiles]
etc., where df_i is based on FILTER == i.
Note that FILTER, although it contains numbers, is actually categorical.
The way I have been doing this is by using dplyr:
nums <- 1:10
library(dplyr)
for (i in nums){
df_temp <- filter(df, FILTER == i)$VALUE
assign(paste0("df_", i), quantile(df_temp, probs = (1:99)/100))
}
and then I would have to cbind these (with 1:99 in the first column), but I would rather not type in every single df name. I have considered using a loop on the names of these data frames, but this would involve using eval(parse()).
Here's a basic outline of a possibly smoother approach. I have not included every single aspect of your desired output, but the modification should be fairly straightforward.
df <- data.frame(FILTER = rep(1:10, each = 10), VALUE = 1:100)
df_s <- lapply(split(df,df$FILTER),
FUN = function(x) quantile(x$VALUE,probs = c(0.25,0.5,0.75)))
out <- do.call(cbind,df_s)
colnames(out) <- paste0("df_",colnames(out))
> out
df_1 df_2 df_3 df_4 df_5 df_6 df_7 df_8 df_9 df_10
25% 3.25 13.25 23.25 33.25 43.25 53.25 63.25 73.25 83.25 93.25
50% 5.50 15.50 25.50 35.50 45.50 55.50 65.50 75.50 85.50 95.50
75% 7.75 17.75 27.75 37.75 47.75 57.75 67.75 77.75 87.75 97.75
I did this for just 3 quantiles to keep things simple, but it obviously extends. And you can add the 1:99 column afterwards as well.
I suggest that you use a list.
list_of_dfs <- list()
nums <- 1:10
for (i in nums){
list_of_dfs[[i]] <- nums*i
}
df <- data.frame(list_of_dfs[[1]])
df <- do.call("cbind",args=list(df,list_of_dfs))
colnames(df) <- paste0("df_",1:10)
You'll get the result you want:
df_1 df_2 df_3 df_4 df_5 df_6 df_7 df_8 df_9 df_10
1 1 2 3 4 5 6 7 8 9 10
2 2 4 6 8 10 12 14 16 18 20
3 3 6 9 12 15 18 21 24 27 30
4 4 8 12 16 20 24 28 32 36 40
5 5 10 15 20 25 30 35 40 45 50
6 6 12 18 24 30 36 42 48 54 60
7 7 14 21 28 35 42 49 56 63 70
8 8 16 24 32 40 48 56 64 72 80
9 9 18 27 36 45 54 63 72 81 90
10 10 20 30 40 50 60 70 80 90 100
How about using get?
df <- data.frame(1:10)
for (i in nums) {
df <- cbind(df, get(paste0("df_", i)))
}
# get rid of first useless column
df <- df[, -1]
# get names
names(df) <- paste0("df_", nums)
df

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