The String class of the java.lang package represents set of characters. All string literals in Java programs, such as "abc", are implemented as instances of this class. A string index is an integer representing the position of each character in the string starting from zero.A substring is a part/segment of a string. You can identify a substring of a string using the substring() method of the String class. This method have two variants −substring(int beginIndex)This method accepts an integer value representing an index in the current string and returns the substring starting from the given index to the end of ... Read More

If we have a character column that means we are more likely to have duplicated values in that column hence finding the mean of numerical columns based on the values in character column cannot be done directly. For this purpose, we can use aggregate function as shown in the below examples.Example1Consider the below data frame − Live Demoset.seed(214) x1

Depending on our objective, a matrix rows might be needed to converted into a list that means each row will be an element of the list. This can be done by using the function as.list but firstly we need to convert the matrix into data frame after transposing. For example, if we have a matrix called M then it’s rows will be converted to a list using the command writtem below −as.list(data.frame(t(M)))Example1 Live DemoM1

To create the bins for a continuous vector, we can use cut function and store the bins in a data frame along with the original vector. The values in the cut function must be passed based on the range of the vector values, otherwise, there will be NA’s in the bin values. For example, if we have a vector that contains 0.55 and we do not use 0 in the cut function then the first bin will be NA. Check out the below examples to understand how to properly do it.Example1 Live Demox1

Sometimes numerical values are recorded as character values and we need to convert them to numeric type before starting our analysis. This is also possible for a whole data frame in R. Therefore, we can use sapply function to convert the columns of the data frame to numeric type and save the output in a data frame by reading it with as.data.frame.Example1Consider the below data frame − Live Demox

The boxplot in base R is covered with a box and that box is called a frame. We can get rid of that frame by using frame argument while creating the boxplot. For example, if we have a vector called x and we want to create the boxplot without frame then it can be done by using the command boxplot(x,frame=F). This will remove all the sides of the boxplot except the Y−axis labels because this will help us to understand the distribution of the variable.Example Live Demox

If there are missing values in a vector then the plot of such vector will not have all the values, only the non−missing values will be shown. If we want to create the plot by adding the missing values in the plot then we need to define the X−axis for the length of the vector and the Y−axis with the actual vector using cbind but missing values will be omitted as shown in the below example.Example Live Demox

Whenever we print any vector then the left-hand side of the R window shows indexing, even if we have one value in the vector the index will be there. For example, if we print a vector that has value equal to 2 then the print output will be [1] 2, here [1] represents the index. If we want to print the vector without index then cat function can be used as shown in the below examples.Example1 Live Demox1

The exponential numbers are also called scientific numbers and these numbers have exponent representation by the letter e. For example, a number 12340000 can be represented as 1.234e + 107. We can round this to 1.2e + 107 and in R it can be done with the help of singif function.Example1 Live Demox1

We know that some years are leap years and some are normal years. The leap years have 366 days and the normal years have 365 days. To create a vector with all dates in a particular year we can use first date and the last date of the year by reading them with as.Date and creating a sequence with seq function. Check out the below examples to understand how it is done.Example1Creating a vector with dates in year 2020 − Live Demoseq(as.Date("2020-01-01"), as.Date("2020-12-31"), by="1 day")Output[1] "2020−01−01" "2020−01−02" "2020−01−03" "2020−01−04" "2020−01−05" [6] "2020−01−06" "2020−01−07" "2020−01−08" "2020−01−09" "2020−01−10" [11] "2020−01−11" "2020−01−12" "2020−01−13" "2020−01−14" ... Read More