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Page 1210 of 2109
How to check in R whether a matrix element is present in another matrix or not?
We can use %in% to check whether a matrix element is present in another matrix or not. For example, suppose we have two matrices defined as − M1 1 2 3 1 2 3 1 2 3 M2 1 2 3 4 5 6 7 8 9Then M1%in%M2 will return −[1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUEBut M2%in%M1 will return −[1] TRUE FALSE FALSE TRUE FALSE FALSE TRUE FALSE FALSEExample1M1
Read MoreHow to combine two factor vectors to create one in R?
To combine two factor vectors, we can extract the unique levels of both the vectors then combine those levels. This can be done by using unique function. Also, we can set the levels of the original vectors to the combination of the levels, in this way, we can complete both the vectors with missing levels. Check out the examples below to understand how it works.Example1x1
Read MoreHow to repeat a random sample in R?
The random sample can be repeated by using replicate function in R. For example, if we have a vector that contains 1, 2, 3, 4, 5 and we want to repeat this random sample five times then replicate(5, x) can be used and the output will be matrix of the below form:[, 1] [, 2] [, 3] [, 4] [, 5] [1, ] 1 1 1 1 1 [2, ] 2 2 2 2 2 [3, ] 3 3 3 3 3 [4, ] 4 4 4 4 4 [5, ] 5 5 5 5 5Example 1> x1 x1Output[1] 1 ...
Read MoreHow to find the cumulative sums by using two factor columns in an R data frame?
Generally, cumulative sums are calculated for a single variable and in some cases based on a single categorical variable, there are very few situations when we want to do it for two categorical variables. If we want to find it for two categorical variables then we need to convert the data frame to a data.table object and use the cumsum function to define the column with cumulative sums.ExampleConsider the below data frame:> set.seed(1361) > Factor1 Factor2 Response df1 df1OutputFactor1 Factor2 Response 1 A T2 9 2 B T1 8 3 B T1 2 4 A T2 3 5 B T1 ...
Read MoreHow to remove a common suffix from column names in an R data frame?
To remove a common suffix from column names we can use gsub function. For example, if we have a data frame df that contains column defined as x1df, x2df, x3df, and x4df then we can remove df from all the column names by using the below command:colnames(df) x1Data x2Data x3Data df1 df1Outputx1Data x2Data x3Data 1 29.26500 26.64124 2.598983 2 21.82170 23.41442 4.134393 3 22.71918 25.21586 4.442823 4 19.88633 25.23487 3.338448 5 20.48989 23.33683 3.829757 6 29.07910 25.54084 3.519393 7 24.28573 23.67258 4.667397 8 27.99849 22.97148 4.100405 9 23.48148 25.36574 2.618030 10 26.39401 23.80191 4.235092 11 29.39867 24.36261 2.782559 12 30.11137 ...
Read MoreHow to count the number of values that satisfy a condition in an R vector?
Sometimes we want to find the frequency of values that satisfy a certain condition. For example, if we have a vector say x that contains randomly selected integers starting from 1 and ends at 100, in this case we might want to find how many values are exactly equal to 10. This can be done by using which and length function.Example1> x1 x1Output[1] 5 7 3 3 2 7 3 7 6 3Example> length(which(x1==5)) [1] 1 > length(which(x1==7)) [1] 3 > length(which(x1==3)) [1] 4Example2> x2 x2Output[1] 4 1 5 5 5 3 8 9 8 4 8 1 6 3 ...
Read MoreHow to create a row sum and a row product column in an R data frame?
To create a row sum and a row product column in an R data frame, we can use rowSums function and the star sign (*) for the product of column values inside the transform function. For example, if we have a data frame df that contains x, y, z then the column of row sums and row product can be created as:transform(df, RowSums=rowSums(df), RowProducts=x*y*z)ExampleConsider the below data frame:> set.seed(3251) > x1 y1 z1 a1 b1 df1 df1Outputx1 y1 z1 a1 b1 1 2 4 10 10 5 2 0 9 5 5 8 3 4 7 6 12 9 4 ...
Read MoreProgram to find angle between hour and minute hands of a clock in C++?
Suppose we have two values hours and minutes. We have to find a smaller angle formed between the hour and the minute hand.So, if the input is like hour = 12 minutes = 45, then the output will be 112.5To solve this, we will follow these steps:if h = 12, then set h := 0if m = 60, then set m := 0hAngle := 0.5 * (60h) + mmAngle := 6mret := |hAngle - mAngle|return minimum of ret and (360 – ret)Let us see the following implementation to get better understanding:Example#include using namespace std; class Solution { public: ...
Read MoreHow to check whether a column value is less than or greater than a certain value in R?
To check whether a column value is less than or greater than a certain value, we can use with function and the output will be a logical vector representing values with TRUE when the condition is satisfied and FALSE when the condition is not satisfied. For example, if we have a column say x of an R data frame df and we want to check whether any of the values in x is greater than 10 or not then it can be done by using with(df, df$x>10).ExampleConsider the below data frame:> set.seed(1002) > x1 y1 z1 df1 df1Outputx1 y1 z1 ...
Read MoreProgram to find cost to remove consecutive duplicate characters with costs in C++?
Suppose we have a string with lowercase letters and we also have a list of non-negative values called costs, the string and the list have the same length. We can delete character s[i] for cost costs[i], and then both s[i] and costs[i] is removed. We have to find the minimum cost to delete all consecutively repeating characters.So, if the input is like s = "xxyyx" nums = [2, 3, 10, 4, 6], then the output will be 6, as we can delete s[0] and s[3] for a total cost of 2 + 4 = 6.To solve this, we will follow ...
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