Finding the 10 Closest Values to 100 and the 30 Closest Ones to 30

In this article, we will explore a problem that involves finding the values in a dataset that are closest to two given numbers, 100 and 30. We will use R programming language to solve this problem.

Introduction

In data analysis, it is often necessary to find the values in a dataset that are closest to a specific number or range of numbers. This can be useful for identifying outliers or finding values that are most representative of a certain group.

The problem we will tackle here involves finding the 10 houses that best fit the description “price close to 100 and size close to 30”. The data is stored in a R dataframe named data_struct.

Step 1: Data Preparation

Before we can find the closest values, we need to prepare our data for analysis. We will subtract the mean of the price and size columns from each value in these columns.

# Calculate the means of price and size
mean_price <- mean(data$price)
mean_size <- mean(data)size)

# Subtract the means from the price and size values
aux <- abs(data - t(replicate(nrow(data), c(mean_size, mean_price))))

Step 2: Find the Absolute Differences

Next, we need to find the absolute differences between the subtracted values and zero. This will give us the distance of each value from the two given numbers.

# Find the absolute differences
aux <- abs(aux)

Step 3: Rank the Columns and Rows

We now need to rank the columns (price and size) based on their distances to 100 and 30 respectively. We will then rank the rows of our dataframe based on these rankings.

# Rank the columns and rows
f <- function(price, size, k, data) {
  aux <- abs(data - t(replicate(nrow(data), c(size, price))))
  data[order(rank(rowSums(as.data.frame(lapply(aux, rank)))))[1:k], ]
}

# Find the 10 closest houses to price=100 and size=30
f(price=100, size=30, k=10, data=data_struct[1:2])

Step 4: Interpret Results

The f function returns a dataframe that contains the 10 closest values to 100 and 30.

# The results
new_baltimore.SQFT new_baltimore.PRICE
2               28.920               113.0
4               26.120               104.3
42              24.940               112.0
54              23.520               110.0
58              35.520                74.0
41              23.040               107.0
151             35.940                85.5
8               25.600                64.5
88              27.480                59.0
52              21.975                85.9

Conclusion

In this article, we have explored how to find the closest values in a dataset to two given numbers, 100 and 30. We have used R programming language to solve this problem.

This technique can be applied to any dataset that contains numeric columns and is useful for identifying outliers or finding values that are most representative of a certain group.

We have also expanded on the original Stack Overflow solution provided by using Hugo’s highlight shortcode to format our code blocks, making it easier to understand and read.

Last modified on 2023-10-22