Branches of mechanical engineering: Get-Your-Stuff-In-Order Exercises + Solutions - R

(This article was get-go published on R-exercises, together with kindly contributed to R-bloggers)

In the exercises below nosotros embrace the basics of ordering vectors, matrices together with information frames. We see both column-wise together with row-wise ordering, unmarried together with multiple variables, ascending together with descending sorting, together with sorting based on numeric, graphic symbol together with ingredient variables. Before proceeding, it mightiness survive helpful to hold off over the assistance pages for the sort, order, and xtfrm functions.

Answers to the exercises are available here.

If yous obtained a unlike (correct) answer than those listed on the solutions page, delight experience costless to postal service your answer every bit a comment on that page.

Exercise 1
Sort the vector x <- c(1, 3, 2, 5, 4) in:
a. ascending order
b. descending order

Exercise 2
Sort the matrix x <- matrix(1:100, ncol=10):
a. inwards descending social club yesteryear its minute column (call the sorted matrix x1)
b. inwards descending social club yesteryear its minute row (call the sorted matrix x2)

Exercise 3
Sort exclusively the get-go column of x in descending order.

Exercise 4
Consider the women data.
a. Confirm that the information are sorted inwards increasing social club for both the height and weight variable, without looking at the data.
b. Create a novel variable bmi, based on the next equation: BMI = ( Weight inwards Pounds / (Height inwards inches) x (Height inwards inches) ) x 703. Check, over again without looking at the data, whether BMI increases monotonically amongst weight together with height.
c. Sort the dataframe on bmi, together with its variable names alphabetically

Exercise 5
Consider the CO2 data.
a. Sort the information based on the Plant variable, alphabetically. (Note that Plant is a factor!). Check that the information are sorted correctly yesteryear printing the information on the screen.
b. Sort the information based on the uptake (increasing) and Plant (alphabetically) variables (in that order).
c. Sort again, based on uptake (increasing) and Plant (reversed alphabetically), inwards that order.

Exercise 6
Create a dataframe df with forty columns, every bit follows:
df <- as.data.frame(matrix(sample(1:5, 2000, T), ncol=40))
a. Sort the dataframe on all forty columns, from left to right, inwards increasing order.
a. Sort the dataframe on all forty columns, from left to right, inwards decreasing order.
c. Sort the dataframe on all forty columns, from right to left, inwards increasing order.

Image: en:User:RolandH [GFDL, CC-BY-SA-3.0 or CC BY-SA 2.5-2.0-1.0], via Wikimedia Commons

_____________________________

Below are the solutions to these exercises on sorting together with ordering.

############### #             # # Exercise 1  # #             # ###############  x <- c(1, 3, 2, 5, 4) sort(x) 

## [1] 1 two iii four v 

sort(x, decreasing=T) 

## [1] v four iii two 1 

############### #             # # Exercise two  # #             # ###############  x <- matrix(1:100, ncol=10) x1 <- x[order(-x[,2]), ] x2 <- x[, order(-x[2, ])]  ############### #             # # Exercise iii  # #             # ###############  x[, 1] <- sort(x[, 1], decreasing=T)  ############### #             # # Exercise four  # #             # ###############  is.unsorted(women$height) 

## [1] FALSE 

is.unsorted(women$weight) 

## [1] FALSE 

women$bmi <- women$weight  / women$height^2 * 703 is.unsorted(women$bmi) 

## [1] TRUE 

women <- women[order(women$bmi), sort(names(women))]  ############### #             # # Exercise v  # #             # ###############  CO2 <- CO2[order(as.character(CO2$Plant)), ] CO2 <- CO2[order(CO2$uptake, as.character(CO2$Plant)), ] CO2 <- CO2[order(CO2$uptake, -xtfrm(as.character(CO2$Plant))), ]  ############### #             # # Exercise half dozen  # #             # ###############  df <- as.data.frame(matrix(sample(1:5, 2000, T), ncol=40)) df <- df[do.call(order, df), ] df <- df[do.call(order, -df), ] df <- df[do.call(order, rev(df)), ]

Sources: 

http://www.r-exercises.com/2016/03/01/get-your-stuff-in-order-exercises/

http://www.r-exercises.com/2016/03/01/get-your-stuff-in-order-solutions/

Sumber http://engdashboard.blogspot.com/

Tweet

Jangan sampai ketinggalan postingan-postingan terbaik dari Branches of mechanical engineering: Get-Your-Stuff-In-Order Exercises + Solutions - R. Berlangganan melalui email sekarang juga:

Bali Attractions