Recent questions tagged R

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Q: Find the name of the column with the minimum date using dplyr

I have the following data frame, I want to find the name of the column with the minimum date for ... JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)...

asked Apr 14, 2022 in Education by JackTerrance

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Q: Trying to make mutate_at work with strptime

I have the following data frame: df = data.frame(date = "23-12-09 22:52") This code works fine ... , JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)...

asked Apr 9, 2022 in Education by JackTerrance

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Q: Use data.table instead of pivot_longer

I would like some help to adjust the output called adjusted that I generate. My idea is to optimize somehow to ... dplyr) library(tidyr) library(lubridate) library(data.table) df1...

asked Apr 7, 2022 in Education by JackTerrance

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Q: Overlay geom_sf onto ggplot

I have a list of ggplots of simple ggplot line graphs based on a location. I created a list of ggplot ... (rnaturalearthdata) library(dplyr) library(ggthemes) #create line plot x...

asked Apr 7, 2022 in Education by JackTerrance

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Q: Use data.table instead of pivot_longer

I would like some help to adjust the output called adjusted that I generate. My idea is to optimize somehow to ... dplyr) library(tidyr) library(lubridate) library(data.table) df1...

asked Apr 7, 2022 in Education by JackTerrance

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Q: Get the product of non-zero element of sparse banded matrix and vector in R

I have a large banded sparse matrix S with few non-zero elements in its rows and columns. And I have vector b, I want to calculate sum(S* ... = (row(S)(col(S)+bw)) S[pick] = 0 S.r...

asked Apr 2, 2022 in Education by JackTerrance

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Q: Which of these types cannot be used to initiate a generic type?

Which of these types cannot be used to initiate a generic type? (a) Integer class (b) Float class (c) ... in section Generics of Java Select the correct answer from above options...

asked Feb 22, 2022 in Education by JackTerrance

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Q: Which of these instance cannot be created?

Which of these instance cannot be created? (a) Integer instance (b) Generic class instance (c) Generic type ... Generics of Java Select the correct answer from above options...

asked Feb 22, 2022 in Education by JackTerrance

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Q: expand a dataframe as given by variables in another dataframe

Can someone help with this: in a new df2 var2 should be added and df2$var1 should be expanded by df1$var2, filling new lines in Var1 & Var3 as given by variables in df1: (df1...

asked Feb 19, 2022 in Education by JackTerrance

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Q: In which year R-Core group was formed?

asked Feb 16, 2022 in Education by JackTerrance