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R Programming Articles
Page 163 of 174
How to change the color of lines for a line chart using ggplot2 in R?
When we create line chart with each of the lines having different color, we might want to change the color of lines if the colors we used at the first time are not making the chart attractive. This can be done by manually setting the color of the lines in the chart with the help of scale_color_manual function.ExampleConsider the below data frame −> set.seed(2) > Group Time Frequency df df Group Time Frequency 1 1 Time1 3 2 2 Time2 6 3 3 Time1 5 4 4 Time2 3 5 5 Time1 9 6 1 Time2 9 7 ...
Read MoreHow to view saved Rdata file in windows?
We save our data files created in R to use them in the future and these files have an extension .Rdata. To view these files, we can make use of load function that will read the path of the file on your system. Suppose you save the file in Documents folder as I do then you will have to provide the path of the Documents folder and that’s it.ExampleSuppose that you created a data frame df and saved it as df.Rdata file in your system −> set.seed(99) > x1 x2 x3 df df x1 x2 x3 1 2 0.7542310 3.3730539 ...
Read MoreHow to plot a function in R?
Plotting a function in R is not a difficult task. We can do it simply with curve function but if the function is very complex then it inside curve function might be difficult. It totally depends on the understand of the person who wants to plot the function, if he or she is well versed with the function then it won’t take much time, otherwise it becomes tedious.Example> curve(exp(x),from=0, to=10)Output> curve((x-1)/(x^2),from=0, to=20,ylab="y")Output> curve(((exp(x))^2)/(x),from=20, to=100,ylab="y")Output
Read MoreHow to filter column values for some strings from an R data frame using dplyr?
Filtering data helps us to make desired groups of data than can be further used for analysis. In this way, accuracy can be achieved and computation becomes easy. Suppose, we have a homogeneous group then to partition that group based on some characteristics the filter function of dplyr package can be used.ExampleConsider the below data frame −> Subject Score df head(df, 20) Subject Score 1 Stats 88 2 Stats 20 3 Stats 49 4 Stats 31 5 Stats 83 6 Physics 29 7 Physics 43 8 Physics 73 9 Physics 28 10 Physics 74 11 Physics 93 12 Physics ...
Read MoreHow to find the unique rows based on some columns in R?
Especially when the experimental conditions are same then we expect some of the row values for some columns to be the same, it is also done on purpose while designing the experiments to check the fixed effect of variables. If we want to determine the unique rows then it can be done by using unique function in R.ExampleConsider the below data frame −> x1 x2 x3 df df x1 x2 x3 1 1 1 A 2 1 1 B 3 1 2 C 4 1 2 D 5 2 2 E 6 2 2 F 7 2 3 G 8 ...
Read MoreHow to remove partial string after a special character in R?
Sometimes we don’t require the whole string to proceed with the analysis, especially when it complicates the analysis or making no sense. In such type of situations, the part of string which we feel that is not necessary can be removed from the complete string. For example, suppose we have a string ID:00001-1 but we don’t want -1 in this string then we can remove it and this can be done with the help of gsub function.Example> x1 gsub("\-.*", "", x1) [1] "ID:00001" "ID:00100" "ID:00201" "ID:014700" "ID:12045" "ID:00012" "ID:10078" > x2 gsub("\/.*", "", x2) [1] "ID:00001" "ID:00100" "ID:00201" "ID:014700" "ID:12045" ...
Read MoreHow to convert a string in an R data frame to NA?
We often see mistakes in data collection processes and these mistakes might lead to incorrect results of the research. When the data is collected with mistakes, it makes the job of analyst difficult. One of the situations, that shows the data has mistakes is getting strings in place of numerical values. Therefore, we need to convert these strings to NA in R so that we can proceed with our intended analysis.ExampleConsider the below data frame −> x1 x2 df df x1 x2 1 1 67 2 3 67 3 6 67 4 7 67 5 5 XYZ 6 2 XYZ ...
Read MoreHow to combine two vectors by separating with different special characters in R?
The combination of two vectors is used for many purposes such as performing two-way ANOVA, presenting data table, or making visual representation of the data. The combinations can be created with many special characters in R by using paste and rep function.ExampleConsider the below vectors Class and Names.> Class Class [1] "Stats" "Maths" "Chem" "Physics" "O-R" > Names Names [1] 101 102 103 104 105Suppose we want to combine Class and Names in a way that the new vector contains Stats|101, Stats|102, and so on. Also, we want to do the same with different special characters.We can do this by ...
Read MoreHow to convert data frame values to a vector by rows in R?
Data can be supplied to us in any form but it is possible that it is not the appropriate one that should be used for analysis. Sometimes data is recorded in a data frame but we might need it as a vector. In such type of situation, we have to change the values of our data frame in a vector. This can be done by reading the data frame values by reading them as.vector after transposing the data frame with t.ExampleConsider the below data frame −> x1 x2 x3 df df x1 x2 x3 1 1 1 5 2 ...
Read MoreHow to deal with error "$ operator is invalid for atomic vectors" in R?
This error occurs because $ operator is not designed to access vector elements. If we use $ operator to access the vector elements then R does not understand it and consider it invalid, therefore, we must be very careful about where we should use $ operator. It happens when we give a name to our elements and start thinking that we can treat them as data frame columns which is a wrong approach. To access the vector elements, we should use single square brackets.ExampleConsider the below vector −> set.seed(1) > x1 x1 [1] 9 4 7 1 2 7 2 ...
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