Remove Line Numbers from Data Table Object in R

Nizamuddin Siddiqui
Updated on 05-Nov-2021 06:31:38

2K+ Views

To remove line numbers from data.table object in R, we can set row.names to FALSE and print the data.table object.For Example, if we have a data.table object called DT then we can remove line numbers from DT by using the command given below −print(DT,row.names=FALSE)Example 1To load data.table object and create an object use the following snippet to create a data frame −library(data.table) x1

Create Stacked Bar Plot for One Categorical Variable in R DataFrame

Nizamuddin Siddiqui
Updated on 05-Nov-2021 06:20:11

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To create stacked bar plot for one categorical variable in an R data frame, we can use ggplot function and geom_bar function of ggplot2 and provide 1 as the X variable inside aes.For Example, if we have a data frame called df that contains a one categorical column say C and one numerical column Num then we can create the stacked bar plot by using the below command −ggplot(df,aes(1,Num,fill=C))+geom_bar(stat="identity")ExampleFollowing snippet creates a sample data frame −x

Find Value in R Data Frame Column That Exists N Times

Nizamuddin Siddiqui
Updated on 05-Nov-2021 06:15:19

212 Views

To find the value in an R data frame column that exist n times, we first need to tabulate the column with factor then extracting the levels of the column after that reading them with as.numeric.Check out the Examples given below to understand how it can be done.Example 1Following snippet creates a sample data frame −x

Round Matrix Values in R

Nizamuddin Siddiqui
Updated on 05-Nov-2021 06:06:36

4K+ Views

To round matrix values, we can use round function.For Example, if we have a matrix called M and we want to round the value in M to 2 decimal places by using the below command −M

Maximum Subarray Sum After Dividing Array into Subarrays in Java

Sunidhi Bansal
Updated on 05-Nov-2021 06:04:04

376 Views

We are given two integer arrays, one having the elements which are computed and other having split points which are required to split the array for making subset and we have to calculate the sum of each subset in every split and return the maximum subset sum.Let us understand with example:-Input − int arr[] = int arr[] = { 9, 4, 5, 6, 7 } int splitPoints[] = { 0, 2, 3, 1 };Output − Maximum subarray sum after each split [22, 13, 9, 9]Explanation − Here we are breaking the array according to their split points and obtaining the maximum subset sum ... Read More

Find Array Using Different XORs of Elements in Groups of Size 4 in Java

Sunidhi Bansal
Updated on 05-Nov-2021 06:03:24

198 Views

We are given with an integer array of size N(size of multiple 4) and we have to perform Xclusive OR operation on the array such that input[1- 4] resembles utility_arr[1- 4] and the conditions of computing is If arr[1 – 4] = {a1, a2, a3, a4} then q[1 – 4] = {a1 ⊕ a2 ⊕ a3, a1 ⊕ a2 ⊕ a4, a1 ⊕ a3 ⊕ a4, a2 ⊕ a3 ⊕ a4}Let us see various input output scenarios for this -In − int[] input = { 5, 2, 3, 4 };Out − Result after XOR operation 4 3 2 5Explanation −An Exclusive-OR gate's output ... Read More

Display Numbers with Decimal in R Data Frame Column

Nizamuddin Siddiqui
Updated on 05-Nov-2021 05:59:31

7K+ Views

To display numbers with decimal in R data frame column, we can use format function with round function and nsmall argument.For Example, if we have a data frame called df that contains an integer column say X then we can display numbers in X with 2 decimal places by using the below command −df$X

Change Decimal Point of Values in R Data Frame Column

Nizamuddin Siddiqui
Updated on 05-Nov-2021 05:54:26

4K+ Views

To change the decimal point of every value in an R data frame column, we can use round function.For Example, if we have a data frame called df that contains a column say X and we want to have each value with 3 decimal places then we can use the below command −df$X

Why Mean of Normal Random Variable with rnorm is Not 10 in Manual Calculation

Nizamuddin Siddiqui
Updated on 05-Nov-2021 05:49:19

110 Views

When we find the mean of normal random variable which is created with rnorm(“sample_size”, 10) is not 10 because rnorm will create a random variable hence mean will be changed but as we increase the sample size the mean will become closer to 10.Check out the Examples given below to understand the variation in the Outputs as the sample size increases.ExampleThe variation in the Outputs of mean of normal random variable created by using rnorm as the sample size increases is explained below −mean(rnorm(100, mean=10)) mean(rnorm(100, mean=10)) mean(rnorm(100, mean=10)) mean(rnorm(100, mean=10)) mean(rnorm(100, mean=10)) mean(rnorm(100, mean=10)) mean(rnorm(100, mean=10)) mean(rnorm(1000, mean=10)) mean(rnorm(1000, ... Read More

Meet in the Middle in Java

Sunidhi Bansal
Updated on 05-Nov-2021 05:34:40

411 Views

We are provided with an array and a sum value; the problem statement is to calculate the maximum subset sum which does not exceed the given sum value. We cannot apply the brute force approach here because the structure of the given array is not the same as the divide and conquer approach.Let us see various input output scenarios for this -Let us understand with exampleInput − long arr[] = { 21, 1, 2, 45, 9, 8 } long given_Sum = 12Output −The maximum sum subset having sum less than or equal to the given sum-->12Explanation −The array is split into a set ... Read More

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