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SLR represents "Simple LR Parser". It is very simple and economical to execute. But it fails to make a parsing table for some class of grammars, i.e., why CLR and LALR are used which implements mainly all class or type of grammars. It constructs parsing tables which helps to perform parsing of input strings.SLR(1) − A grammar having an SLR parsing table is said to be SLR (1).Working of SLR ParserSLR Parsing can be done if context-free Grammar will be given. In LR (0), 0 means there is no Look Ahead symbol.The Canonical collection of LR (0) itemsThe LR (0) ... Read More
To remove rows from a data frame that exists in another data frame, we can use subsetting with single square brackets. This removal will help us to find the unique rows in the data frame based on the column of another data frame.Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −x
SolutionStep1− Construct the Augmented Grammar and number the productions(0) E′ → E(1) E → E + T(2) E → T(3) T → T * F(4) T → F(5) F → (E)(6) F → idStep2− Apply closure to the set of items & find gotoSquare Boxes represent the new states or items, and Circle represents the repeating items.So, all rules of I0have been completed by applying goto on I0. Now, in the same manner apply goto on I1, I2 and then goes on.Drawing DFAEach set of the item can be taken as a state of DFA, i.e., I0, I1 … … ... Read More
To add values in sequence to the previous value with a constant, we can find the cumulative sum of values and add the constant to the Output.For Example, if we have a vector called X and we want to add values in X in sequence to the previous value with a constant say 10 then we can use the command given below −10+cumsum(X)Example 1Following snippet creates a sample data frame −x1
To create cross tabulation for three categorical columns, we can use xtabs function. The xtabs function will create contingency table for each category in two columns and each contingency table will be created for the category in the third column.Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −df1
To change the name of column variable and row variable in xtab table, we can use setNames function.For Example, if we have a xtab table called XTAB and we want to change the column variable name C and row variable name R then we can use the below command −dimnames(XTAB)
To create confusion matrix for a rpart model, we first need to find the predicted values then the table of predicted values and the response variable in the original data can be created, which will be the confusion matrix for the model.For Example, if we have a vector of predicted values say P and original values in data frame df$O then the confusion matrix can be created by using the following command −table(P, df$O)Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −Dep_Var1Read More
We are given an integer as input. The goal is to print the formula of GCD of n numbers using recursion.We know that the GCD of three numbers say a1, b1 and c1 will be gcd(a1, gcd(b1, c1)).Similarly for more than three numbers, gcd can be obtained by formula as gcd ( a1, gcd(b1, gcd(c1….., gcd(y1, z1)).ExamplesInput − Num = 4;Output − Formula is:GCD(int a3, GCD(int a2, GCD(int a1, int b1)))Input − Num = 6;Output − Formula is: GCD(int a5, GCD(int a4, GCD(int a3, GCD(int a2, GCD(int a1, int b1)))))Approach used in the below program is as followsIn this approach we are using the ... Read More
We are given an integer as input. The goal is to find whether the input number Num is a palindrome or not using recursion.To check if a number is palindrome, reverse that number and check if both numbers are the same or not. If the reversed number is equal to the original number, then it is palindrome.ExamplesInput − Num = 34212;Output − 34212 is not a Palindrome!Explanation − If we reverse 34212 then we get 21243. 34212 != 21243 hence the input number is not palindrome.Input − Num = 32123;Output − 32123 is Palindrome!Explanation − If we reverse 32123 then we get 32132. 32123!= 32123 ... Read More