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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to create a scatterplot with colors as group in R?
To create a scatterplot with colors as group, we can define the colors in col argument as characters.For Example, if we have two vectors then we can create scatterplot between x and y with red and blue colors for x and y value by using the below mentioned command −plot(x,y,col=as.character(cut(x,2,labels=c("red","blue"))))ExampleFollowing snippet creates a sample data frame −x
Read MoreCreate a rolling mean column by displaying means to corresponding values in R data frame.
To create a rolling mean column by displaying means to corresponding values in R data frame, we can use ave function with rep function.For Example, if we have a data frame called df that contains a numerical column say X then we can create a rolling mean column for every 5 values by using the below mentioned command −df$Rolling_M_5
Read MoreWhat is assignment statements with Integer types in compiler design?
Assignment statements consist of an expression. It involves only integer variables.Abstract Translation SchemeConsider the grammar, which consists of an assignment statement.S → id = EE → E + EE → E ∗ EE → −EE → (E)E → idHere Translation of E can have two attributes −𝐄. 𝐏𝐋𝐀𝐂𝐄− It tells about the name that will hold the value of the expression.𝐄. 𝐂𝐎𝐃𝐄− It represents a sequence of three address statements evaluating the expression E in grammar represents an Assignment statement. E. CODE represents the three address codes of the statement. CODE for non-terminals on the left is the concatenation of ...
Read MoreCombine two columns in R data frame with comma separation.
To combine two columns in R data frame with comma separation, we can use paste function with sep argument.For Example, if we have two columns say X and Y in a data frame called df then we can combine the values of these two columns in a new column with comma separation by using the below mentioned command −df$Combined
Read MoreHow to find the covariance between two vectors in R?
The covariance is a mathematical measurement to quantify the variation between of two variables together. That means it tells us how two variables under consideration vary together. If we have two vectors and we want to find the covariance between them then we can use the command mentioned below −cov(“First_Vector”,”Second_Vector”)Example 1Following snippet creates a sample data frame −x1
Read MoreConstruct Quadruples, Triples, and Indirect Triples for the expressionn-(a + b) * (c + d) - (a + b + c)
SolutionFirst of all this statement will be converted into Three Address Code as−t1 = a + bt2 = −t1t3 = c + dt4 = t2 ∗ t3t5 = t1 + ct6 = t4 − t5QuadrupleLocationOperatorarg 1arg 2Result(0)+abt1(1)−t1t2(2)+cdt3(3)∗t2t3t4(4)+t1ct5(5)−t4t5t6 TripleLocationOperatorarg 1arg 2(0)+ab(1)−(0)(2)+cd(3)∗(1)(2)(4)+(0)c(5)−(3)(4)Array RepresentationQuadruple is a structure that contains atmost four fields, i.e., operator, Argument 1, Argument 2, ...
Read MoreHow to apply t test on each row of an R data frame?
To apply t test on each row of an R data frame, we can use apply function along with t.test function. For Example, if we have a data frame called DF and we want to apply t test on each row of DF then we can use the command given below −apply(DF,1,t.test)Check out the below Example to understand how it works.ExampleFollowing snippet creates a sample data frame −x
Read MoreWhat is Three Address Code?
The three-address code is a sequence of statements of the form A−=B op C, where A, B, C are either programmer-defined names, constants, or compiler-generated temporary names, the op represents an operator that can be constant or floatingpoint arithmetic operators or a Boolean valued data or a logical operator. The reason for the name “three address code” is that each statement generally includes three addresses, two for the operands, and one for the result.In the three-address code, atmost three addresses are define any statement. Two addresses for operand & one for the result.Hence, op is an operator.An only a single ...
Read MoreWhat is the difference between Parse Tree and the Syntax Tree?
Parse TreeParse tree is a hierarchical structure that defines the derivation of the grammar to yield input strings. In parsing, the string is derived using the start symbol. The root of the parse tree is that start symbol. It is the graphical description of symbols that can be terminals or non-terminals. Parse tree follows the precedence of operators. The deepest sub-tree traversed first. Therefore, the operator in the parent node has less precedence over the operator in the sub-tree.A Parse Tree for a CFG G = (V, Σ, P, S) is a tree satisfying the following conditions −Root has the ...
Read MoreHow to perform one sample Kolmogorov-Smirnov test in R?
The one sample Kolmogorov-Smirnov test is used to check whether a data set follows certain distribution of not.For Example, if we have a vector called X and we want to know whether values in X follow normal distribution or not then we can use the command given below −ks.test(X,"pnorm")Check out the below Examples to understand how it works.Example 1Following snippet creates a sample data frame −x1
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