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Articles on Trending Technologies
Technical articles with clear explanations and examples
Consider the ambiguous grammar.nE → E + EnE → E * EnE → (E)nE → idn(a) Construct LR (0) items for above grammar.n(b) Construct SLR parsing table for grammar.n(c) Parse the input string id + id * id.
Problem Statement Consider the ambiguous grammar.E → E + EE → E * EE → (E)E → id(a) Construct LR (0) items for above grammar.(b) Construct SLR parsing table for grammar.(c) Parse the input string id + id * id. SolutionStep1− Construct Augmented Grammar(0) E′ → S(1) E → E + E(2) E → E ∗ E(3) E → (E)(4) E → idStep2− Find closure & goto functions to construct LR (0) items.Closure (E′ → ∙ E) =Applying goto on I9∵ goto cannot be applied on I9, ...
Read MoreHow to create normal probability plot in R with confidence interval bands?
To create normal probability plot in R with confidence interval bands, we can use qqPlot function of QTLRel package. We simply need to pass the vector name that contains normal distribution values inside qqPlot function or directly introduce the vector inside the function as shown in the below given examples.Example 1Use the following code to create normal probability plot −library("QTLRel") qqPlot(rnorm(10))OutputIf you execute the above given snippet, it generates the following Output −Example 2Add the following code to the above snippet to create normal probability plot −qqPlot(rnorm(500)) OutputIf you execute the above given snippet, it generates the following Output −Example ...
Read MoreCreate a matrix for odd number of elements by filling the last element with NA in R.
We can find the total number of elements for a matrix with the help of prod and dim function as shown in the below Examples. To create a matrix for odd number of elements by filling the last element with NA, we can use byrow argument.For Example, if we have a vector called V that contains 19 elements then we can create a matrix called M having 20 elements NA as the last element by using the below command −M
Read MoreHow to create an ID column in R based on categories?
If we have a categorical column in an R data frame then it can be used to create an ID column where each category will have its own ID defined on the basis of categories in the categorical column.For this purpose, we would need to read the categorical column with as.factor and as.numeric function as shown in the below examples.Example 1Following snippet creates a sample data frame −Group
Read MoreRotate a matrix by 90 degree without using any extra space in C++
We are given a 2-D array that will be used to form a matrix pattern. The task is to rotate a matrix by 90 degrees in an anti-clockwise direction such that the first row becomes the first column, second row becomes second column and third becomes third column and the challenge is that we don’t have to use any extra space.Let us see various input output scenarios for this −Input −int arr[row_col_size][row_col_size] = { { 5, 1, 4}, { 9, 16, 12 }, { 2, 8, 9}}Output −Rotation of a matrix by 90 degree without using any extra space ...
Read MoreHow to create a scatterplot with larger distance between facets in R?
By default, the distance/space between facets created by using ggplot2 is very less and it becomes a little uneasy for viewers to separately read the facets. Therefore, to deal with this problem we can increase the space between facets and it can be done with the help of theme function as shown in the example below.ExampleFollowing snippet creates a sample data frame &miuns;x
Read MoreHow to find the column means for each matrix stored in an R list?
To find the column mean of all matrices stored in an R list, we can use sapply function along with colMeans function.For example, if we have a list called LIST that contains some matrices then the col means for each matrix can be found by using the commandsapply(LIST,colMeans)Check out the below example to understand how it works.ExampleFollowing snippet creates list of matrices −M1
Read MoreHow to randomly assign participants to groups in R?
To randomly assign participants to groups, we can use sample function.For example, if we have a data frame called df that contains a column say Employee_ID and we want to create five groups that are stored in a vector say Grp then random assignment of participants to values in Grp can be done by using the command given below −df$Grp
Read MoreCreate an integer column in an R data frame with leading zeros
To create an integer column in an R data frame with leading zeros, we can use sprintf function.For Example, if we want to create a data frame column having values starting from 1 to 10 and we want to have 1 as 01 and so on then we can use the command given below −data.frame(x=sprintf('%0.2d',1:10))Check out the Examples given below to understand how it works.Example 1To create an integer column in an R data frame with leading zeros, use the command given below −df1
Read MoreHow to change the Y-axis title in base R plot?
The easiest way to change the Y-axis title in base R plot is by using the ylab argument where we can simply type in the title. But the use of ylab does not help us to make changes in the axis title hence it is better to use mtext function, using which we can change the font size, position etc. of the title.Check out the below example to understand how it can be done.ExampleUse the code given below to change the Y-axis title in base R plot −plot(1:10)OutputIf you execute the above given code, it generates the following Output −Add ...
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