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Server Side Programming Articles
Page 1150 of 2109
How to save a csv and read using fread in R?
To save a csv file, we can use write.csv function in R and if we want to read it using fread then fread function will be used with the name of the csv file. The benefit of reading the csv file with fread function is that there will be a variable added to the original csv file which contains the id as integers starting from 1 to the length of column values.Consider the below data frame −Examplex
Read MoreHow to define the breaks for a histogram using ggplot2 in R?
To manually define the breaks for a histogram using ggplot2, we can use breaks argument in the geom_histogram function. While creating the number of breaks we must be careful about the starting point and the difference between values for breaks. This will define the number of bars for histogram so it should be taken seriously and should be according to the distribution of the data.Consider the below data frame −Examplex
Read MoreHow to add an extra point to scatterplot using ggplot2 in R?
To add an extra point to scatterplot using ggplot2, we can still use geom_point function. We just need to use aes function for quoting with new values for the variables, also we can change the color of this point using colour argument. The display of an extra point will help us to distinguish between a threshold/new value and remaining values.Consider the below data frame −Examplex
Read MoreHow to convert binary variable to 0/1 format in an R data frame?
A binary variable is a type of variable that can take only two possible values like gender that has two categories male and female, citizenship of a country with two categories as yes and no, etc. If the binary variable is not in 0/1 format then it can be converted with the help of ifelse function. Check out the below examples to understand how it works.Consider the below data frame −ExampleTemp
Read MoreHow to replace a complete column in an R data frame?
To replace a complete column in an R data frame, we can set the original one to new values by using delta operator. For example, if we have a data frame called df that contains a column x which 500 has values from normal distribution then to replace it with the normal distribution having a mean of 25 can be done as df$x
Read MoreHow to display Y-axis with Euro sign using ggplot2 in R?
When we have a Euro currency column in an R data frame as a response variable then we might to display the Euro sign in the plot created by using ggplot2 package. For this purpose, we can use scales package and the scale for Y axis will be changed by using the command scale_y_continuous(labels=dollar_format(suffix="€",prefix="")) to the plot command.Consider the below data frame −Examplex
Read MoreHow to check whether a particular word exists in an R data frame column?
If we have a character column in an R data frame then we might want to check whether a particular value exist in the column or not. For example, if we have a gender column then we might want to check whether transgender exists in that column or not. This can be done with the help of grepl function. Check out the below examples to understand how it works.Consider the below data frame −Examplex
Read MoreHow to plot time series data with labels in R?
If we have time series data stored in a data frame then plotting the same as a time series cannot be done directly, also the labels for the series might not be possible directly. Therefore, we first need to convert the data frame to a time series object by using the function ts as shown in the below example and then using the plot function to create the plot, this will display the labels for the series as well.Consider the below data frame −ExampleTime
Read MoreHow to collapse data frame rows in R by summing using dplyr?
To collapse data frame rows by summing using dplyr package, we can use summarise_all function of dplyr package. For example, if we have a data frame called df that has a categorical column say Group and one numerical column then collapsing of rows by summing can be done by using the command −df%>%group_by(Group)%>%summarise_all(funs(sum))Consider the below data frame −ExampleGroup
Read MoreHow to change the legend shape using ggplot2 in R?
By default, the shape of legend is circular but we can change it by using the guides function of ggplot2 package. For example, if we have a data frame with two numerical columns say x and y, and one categorical column Group then the scatterplot between x and y for different color values of categories in categorical column Group having different shape of legends can be created by using the below command −ggplot(df, aes(x, y, color=Group))+geom_point()+guides(colour=guide_legend(override.aes=list(shape=0)))Here, we can change the shape argument value to any value between starting from 0 to 25.Consider the below data frame −Examplex
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