Statistics in R

statistics_calculations.R

### Median and Quartile

cal_med <- function(x)
{
    ### median
    x<- sort(x)
    l1 <- length(x)
    mid <- c()
    if(l1 %% 2 == 0) mid <- append(mid, c(l1/2, (l1/2)+1))
    else mid <- append(mid,  ceiling(l1/2))
    
    if(length(mid) != 1) 
    {
        val <- x[mid]
        val <- sum(val) / length(val)
        # cutoff <- l1/2
    } else {
        val <- x[mid]
        # cutoff <- ceiling(l1/2)
    }
    
    return(val)

}

q1_q3 <- function(x)
{
    x <- sort(x)
    if(length(x) %%2 != 0)
    {
        cutoff <- ceiling(length(x)/2)
        q1_ <- x[1:(cutoff - 1)]#; print(q1_)
        q3_ <- x[(cutoff+1):length(x)]#; print(q3_)
    } else {
        cutoff <- c(length(x)/2)
        q1_ <- x[1:cutoff]
        q3_ <- x[(cutoff + 1) : length(x)]
        
    }
    
    q1 <- cal_med(q1_)
    q3 <- cal_med(q3_)
    
    return(list(q_q1 = q1, q_q2 = q3))
    
}

### Standard Deviation

find_sd <- function(x)
{
    get_mean <- sum(x) / length(x)
    
    int_sum <- c()
    for(i in x)
    {
        int_sum <- append(int_sum, (x - get_mean)^2)
        }
    
    int_sum <- sqrt(sum(int_sum)/length(int_sum))
    int_sum <- round(int_sum,1)
    
    return(int_sum)
}

### Interquartile range

con <- file('stdin', 'r')

input <- readLines()
n <- input[[1]]
n1 <- input[[2]]
n2 <- input[[3]]

n1 <- as.numeric(unlist(strsplit(n1, ' ')))
n2 <- as.numeric(unlist(strsplit(n2, ' ')))

vec <- rep(n1, n2)

q1_q3 <- function(x)
{
    x <- sort(x)
    if(length(x) %%2 != 0)
    {
        cutoff <- ceiling(length(x)/2)
        q1_ <- x[1:(cutoff - 1)]#; print(q1_)
        q3_ <- x[(cutoff+1):length(x)]#; print(q3_)
    } else {
        cutoff <- c(length(x)/2)
        q1_ <- x[1:cutoff]
        q3_ <- x[(cutoff + 1) : length(x)]
        
    }
    
    q1 <- cal_med(q1_)
    q3 <- cal_med(q3_)
    
    return(list(q_q1 = q1, q_q3 = q3))
    
}

q1_res <- q1_q3(vec)$q_q1
q3_res <- q1_q3(vec)$q_q2

iqr <- q3_res - q1_res
cat(iqr)

#### get diagonals from vectors

# Enter your code here. Read input from STDIN. Print output to STDOUT

con <- file('stdin', 'r')
input <- readLines(con)

n <- as.numeric(input[[1]])

diag1 <- c()
diag2 <- c()
for (i in seq(2,n+1))
{
    #mats <- append(mats, input[[i]])
    d1 <- as.numeric(unlist(strsplit(input[[i]], ' ')))[i-1]
    diag1 <- append(diag1, d1)
    
    d2 <- as.numeric(unlist(strsplit(input[[i]], ' ')))[(n+2)-i]
    diag2 <- append(diag2, d2)
 
}
#print(diag2)
cat(abs(sum(diag1) - sum(diag2)))