Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles by Nizamuddin Siddiqui
Page 103 of 196
How to subset an R data frame based on string values of a columns with OR condition?
We might want to create a subset of an R data frame using one or more values of a particular column. For example, suppose we have a data frame df that contain columns C1, C2, C3, C4, and C5 and each of these columns contain values from A to Z. If we want to select rows using values A or B in column C1 then it can be done as df[df$C1=="A"|df$C1=="B",].Consider the below data frame −Exampleset.seed(99) x1
Read MoreHow to create a transparent polygon using ggplot2 in R?
A transparent polygon just represents the border lines and a hollow area; thus, we can only understand the area covered but it becomes a little difficult to understand the scales. Hence, this visualisation technique is not as useful as others that fills the area with a different color. But it could be used if the range of the data is not large.Consider the below data frame −Exampleset.seed(123) x
Read MoreHow to find the proportion of row values in an R data frame?
The proportion of row values can be calculated if we divide each row value with the sum of all values in a particular row. Therefore, the total sum of proportions will be equal to 1. This can be done by dividing the data frame with the row sums and for this purpose we can use the below syntax −Syntaxdata_frame_name/rowSums(data_frame_name)Consider the below data frame −Exampleset.seed(111) x1
Read MoreHow to plot all the values of an R data frame?
To plot all the values of an R data frame, we can use matplot function. This function plots all the values based on the columns of an R data frame and represent them by the column number. For example, if we have five columns in an R data frame then matplot will represent the first column by 1, second column by 2, third column by 3 and so on.Consider the below data frame −Exampleset.seed(555) v1
Read MoreHow to split string values that contain special characters in R?
When we have a single long string or a vector of string values and the values within the string are separated by some special characters then splitting the values can help us to properly understand those strings. This could happen in situations when the string data is recorded with mistakes or have some other purpose. We can do the splitting using strsplit function.Examplex1
Read MoreHow to create barplot from data frame in R using rows as categories?
If we have small number of rows then we might want to create bar plot for rows instead of using columns as categories. This can be done by using barplot function but we need to convert the data frame to matrix and take the transpose of it. For example, if we have a data frame data_frame with 4 rows and 4 columns, then the barplot with rows as categories can be created as barplot(t(as.matrix(data_frame)),beside=TRUE)Consider the below data frame −Examplex1
Read MoreHow to renumber rows if they are unordered in R?
When we create a sample using inbuilt or imported data set then the numbering for selected rows as in the original data set, therefore, the numbering becomes unordered. To change this unordered numbering to a sequence say starting from one to the total number of rows in the sample, we can use 1:nrow(“sample_object_name”).Consider the below data frame −Exampleset.seed(999) x
Read MoreHow to split a long string into a vector of substrings of equal sizes in R?
If a vector is recorded as a single string by mistake or the file that contains the data did not separated the string in an appropriate way then we might need to split in the correct form so that we can proceed with the further analysis. This might happen when the levels of a factor variable that have equal name length are not separated. In this case, we can split the string into a vector that contain substring of equal sizes by using substring function.ExamplesJust look at these examples to understand how substring function can help us to split the ...
Read MoreHow to write a long line for the X-label of a scatterplot in R using ggplot2?
When we create a plot in R, the variable names are automatically plotted as axes labels but sometimes we want to give a brief detail of the X-label or a Y-label. If that brief is not small so that the expression function can contain the length of the label then it becomes difficult but it can be done with the help of atop inside expression.ExampleConsider the below data frame −set.seed(123) x
Read MoreHow to remove NULL values from a list in R?
The value NULL is used to represent an object especially a list of length zero. If a list contains NULL then we might want to replace it with another value or remove it from the list if we do not have any replacement for it. To remove the NULL value from a list, we can use the negation of sapply with is.NULL.Examplesx
Read More