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Server Side Programming Articles
Page 1166 of 2109
How to save list where each element contains equal number of values to a text file in R?
If we want to save a list to a text file then first step would be converting that list to a data frame then write.table function can be used for saving. For example, if we have a list defined as LIST and it has elements each containing 50 values then we can convert it to a data frame as −LIST_df=as.data.frame(do.call(cbind,LIST))Now we can save it as −write.table(LIST_df,"LIST.txt")ExampleConsider the below list −x1
Read MoreHow to create a line chart using ggplot2 with larger width in R?
The width of the line chart can be increased by using size argument inside geom_line aesthetics of ggplot2. For example, if we have a data frame df that contains two numerical columns x and y, and we want to create a line chart between the two with larger width then it can be done as −ggplot(df)+geom_line(aes(x,y,size=2))ExampleConsider the below data frame −x
Read MoreHow to create a scatterplot with regression line using ggplot2 with 0 intercept and slope equals to 1 in R?
To create a regression line with 0 intercept and slope equals to 1 using ggplot2, we can use geom_abline function but we need to pass the appropriate limits for the x axis and y axis values. For example, if we have two columns x and y in a data frame df and both have ranges starting from -1 to 1 then the scatterplot with regression line with 0 intercept and slope equals to 1 can be created as −ggplot(df,aes(x,y))+geom_point()+geom_abline()+lims(x=c(-1,1),y=c(-1,1))ExampleConsider the below data frame −x
Read MoreHow to compare two columns in an R data frame for an exact match?
Sometimes analysis requires the user to check if values in two columns of an R data frame are exactly the same or not, this is helpful to analyze very large data frames if we suspect the comparative values in two columns. This can be easily done with the help of ifelse function.ExampleConsider the below data frame −x1
Read MoreHow to identify duplicate values in a column of matrix in R?
We can easily identify duplicate values in a matrix by using duplicated function but it does not specify that the first occurrence is also duplicated. Therefore, we need to use it with OR sign | and the argument fromLast = TRUE of duplicated function so that the first occurrence of the duplicated values will be also identified as duplicate.ExampleM1
Read MoreHow to create side by side histograms in base R?
To create side by side histograms in base R, we first need to create a histogram using hist function by defining a larger limit of X-axis with xlim argument. After that we can create another histogram that has the larger mean and smaller standard deviation so that the bars do not clash with each other and add=T argument must also be added inside the second hist function.Examplehist(rnorm(5000,mean=5,sd=2.1),col="green",xlim=c(1,20))OutputExamplehist(rnorm(5000,mean=15,sd=1.25),col="red",add=T)Output
Read MoreHow to find the mean of a numerical column by two categorical columns in an R data frame?
If we have two categorical columns along with a numerical column in an R data frame then we can find the mean of the numerical column by using the combination of the categorical columns with the help of aggregate function. For example, if a data frame df contains a numerical column X and two categorical columns C1 and C2 then the mean of X can be found for the combinations of C1 and C2 by using the below command −aggregate(X~C1+C2,data=df,FUN="mean")ExampleConsider the below data frame −C1
Read MoreHow to find the column number of a string column based on a string match in an R data frame?
A data frame might be very long and contain columns with only string values as well as numerical values. While doing the analysis, we might want to check which columns contain a particular string value. For example, if we have a column with string values as A, B, and C and we want to check which column contains a value “A” then apply function can be used as shown in the below examples.ExampleConsider the below data frame −x1
Read MoreHow to create the boxplots in base R ordered by means?
To create the boxplots in base R ordered by means, we first need to order the categorical column based on the mean of the numerical column and then the boxplot will be created.For example, if we have a data frame df that has a categorical column x and a numerical column y then the boxplot ordered by means can be created by using df$x
Read MoreHow to create a plot with tick marks between X-axis labels in base R?
To create a plot with tick marks manually between X-axis values in base R, we first need to create the plot without X-axis labels then add the axis values using axis function with appropriate labels, this will create tick marks as well as labels. After this step, we would need to use the axis function again to add the tick marks without labels.Exampleplot(1:10,xaxt='n',type="l") axis(1,at=1:10) axis(1,at=seq(0,11,0.2),labels=NA)OutputExampleplot(1,xaxt='n') axis(1,at=1) axis(1,at=seq(0,2,0.05),labels=NA)Output
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