What does :: in R mean?
In other words ::: is used to directly access a member of a package that is internal (i.e. not exported from the NAMESPACE). See this related question: R: calling a function from a namespace.
The Equality Operator ==
Relational operators, or comparators, are operators which help us see how one R object relates to another. For example, you can check whether two objects are equal (equality) by using a double equals sign == .
Colon operator (":") in R is a function that generates regular sequences. It is most commonly used in for loops, to index and to create a vector with increasing or decreasing sequence.
The pipe operator, written as %>% , has been a longstanding feature of the magrittr package for R. It takes the output of one function and passes it into another function as an argument. This allows us to link a sequence of analysis steps.
Tilde operator is used to define the relationship between dependent variable and independent variables in a statistical model formula. The variable on the left-hand side of tilde operator is the dependent variable and the variable(s) on the right-hand side of tilde operator is/are called the independent variable(s).
%s means its a string, %d is an integer, %f is floating point number. cheers! Submitted by Utsab Shrestha.
== is always for testing equality. in most cases used as a drop-in replacement for <- , the assignment operator. used as the separator for key-value pairs used to assign values to arguments in function calls.
Python Vs R: Full Comparison
R is a statistical language used for the analysis and visual representation of data. Python is better suitable for machine learning, deep learning, and large-scale web applications. R is suitable for statistical learning having powerful libraries for data experiment and exploration.
The standard among statistical programming languages, R is sometimes called the “golden child” of data science. It's a popular skill among Big Data analysts, and data scientists skilled in R are sought after by some of the biggest brands, including Google, Facebook, Bank of America, and the New York Times.
The double-colon operator :: selects definitions from a particular namespace. In the example above, the transpose function will always be available as base::t , because it is defined in the base package. Only functions that are exported from the package can be retrieved in this way.
What does a semi colon mean in R?
Certainly the R documentation doesn't seem to make a distinction with respect to syntactically complete statements: Both semicolons and new lines can be used to separate statements. A semicolon always indicates the end of a statement while a new line may indicate the end of a statement.
It is a colon-separated list of directories in which the shell looks for commands (see COMMAND EXECUTION below). A zero-length (null) directory name in the value of PATH indicates the current directory. A null directory name may appear as two adjacent colons, or as an initial or trailing colon.
4.1 Introduction. Use %>% to emphasise a sequence of actions, rather than the object that the actions are being performed on. Avoid using the pipe when: You need to manipulate more than one object at a time.
The group_by() function in R is from dplyr package that is used to group rows by column values in the DataFrame, It is similar to GROUP BY clause in SQL. R dplyr groupby is used to collect identical data into groups on DataFrame and perform aggregate functions on the grouped data.
c() function in R Language is used to combine the arguments passed to it.
The Basics: mean() and sd()
Calculating an average and standard deviation in R is straightforward. The mean() function calculates the average and the sd() function calculates the standard deviation.
- mutate() – adds new variables while retaining old variables to a data frame.
- transmute() – adds new variables and removes old ones from a data frame.
- mutate_all() – changes every variable in a data frame simultaneously.
- mutate_at() – changes certain variables by name.
Most new codes are actually developed by English-speaking individuals. But not all programming codes are in English. Although most keywords are written in English, comments, variable user written classes and methods are often in the programmer's own language.
...
Diseconomies of Scale and Lines of Code.
| Project Size | Lines of code (per year) | COCOMO average |
|---|---|---|
| 100,000 LOC | 1,000 - 20,000 | 2,600 |
| 1,000,000 LOC | 700 - 10,000 | 2,000 |
| 10,000,000 LOC | 300 - 5,000 | 1,600 |
With the help of no-code platforms, it's possible to develop software without writing any underlying code.
Is Python or R harder?
R can be challenging for beginners to learn due to its nonstandardized code. Python is usually easier for most learners and has a smoother linear curve. In addition, Python requires less coding time since it's easier to maintain and has a syntax similar to the English language.
R is known for being hard to learn. This is in large part because R is so different from many programming languages. The syntax of R, unlike languages like Python, is very difficult to read. Basic operations like selecting, naming, and renaming variables are more confusing in R than they are in other languages.
Companies use R
The other reason why Python is wining is its robust libraries that makes the programming language more powerful especially when it comes to Machine Learning, Deep Learning and Artificial Intelligence in general.
R and Excel are beneficial in different ways. Excel starts off easier to learn and is frequently cited as the go-to program for reporting, thanks to its speed and efficiency. R is designed to handle larger data sets, to be reproducible, and to create more detailed visualizations.
In the context of biomedical data science, learn Python first, then learn enough R to be able to get your analysis done, unless the lab that you're in is R-dependent, in which case learn R and fill in the gaps with enough Python for easier scripting purposes. If you learn both, you can R code into Python using rpy.
If you have experience in any programming language, it takes 7 days to learn R programming spending at least 3 hours a day. If you are a beginner, it takes 3 weeks to learn R programming.
Colon ':' is basically a operator which indicates that the y is inside x and assign the y's value to the elements of array one by one.
paste(): Takes multiple elements from the multiple vectors and concatenates them into a single element. Along with paste() function, R has another function named paste0().
R doesn't need semicolons to end a line of code (while it's possible to put multiple commands on a single line separated by semicolons, you don't see that very often). Instead, R uses line breaks (i.e., new line characters) to determine when an expression has ended.
The Semicolon lets the compiler know that it's reached the end of a command. Semicolon is often used to delimit one bit of C++ source code, indicating it's intentionally separated from the respective code.
What is the difference between and [[ ]] in R?
The difference between them is that [[ ]] is used to access a component in a list or matrix whereas [ ] is used to access a single element in a matrix or array.
The tail() function in R
The tail() function in the R is particularly used to display the last n rows of the dataset, in contrary to the head() function.
A colon is used to give emphasis, present dialogue, introduce lists or text, and clarify composition titles. Emphasis—Capitalize the first word after the colon only if it is a proper noun or the start of a complete sentence.
- Introducing a list. The colon is used to introduce a list of items. ...
- Between independent clauses when the second explains or illustrates the first. The colon is used to separate two independent clauses when the second explains or illustrates the first. ...
- Emphasis.
On Windows systems, files and directory names cannot be created with a colon (:). But if a file or directory name is created with a colon on a Linux or Mac operating system, then moved to a Windows system, percent encoding is used to include the colon in the name in the index.
tidyr is the Tidyverse package for getting data frames to tidy. Recall that in a tidy data frame: each row is a unit of observation. each column is a single piece of information.
Tidyverse graph automation
As you can see, the tidyverse version is a bit faster compared to the for-loop, but it is not impressive (188150 ms vs. 218730 ms). The loop is 1,16 times slower whereas the tidyverse version of the code brings a speed boost of approx. 14%.
Pipes let you take the output of one function and send it directly to the next, which is useful when you need to many things to the same data set. Pipes in R look like %>% and are made available via the magrittr package installed as part of dplyr .
In this SQL tutorial, we will learn how to use Order by and Group By in SQL. Group By in SQL is used to arrange similar data into groups and Order By in SQL is used to sort the data in ascending or descending order.
By using group_by() function from dplyr package we can perform group by on multiple columns or variables (two or more columns) and summarise on multiple columns for aggregations.
How do I split data into two groups in R?
Split vector and data frame in R, splitting data into groups depending on factor levels can be done with R's split() function. Split() is a built-in R function that divides a vector or data frame into groups according to the function's parameters.
By using na. omit() , complete. cases() , rowSums() , and drop_na() methods you can remove rows that contain NA ( missing values) from R data frame.
Use of R in Financial Formulas
If there are multiple returns used in a calculation, they are often given subscript letters. In formulas, lower case "r" usually represents the required rate of return. RE is usually expected return.
OR Operator “|”
This means that TRUE | TRUE equals TRUE , but also, TRUE | FALSE and FALSE | TRUE evaluates to TRUE . When both logicals are FALSE in an OR operation, so in the case of FALSE | FALSE , the result is FALSE . Remember, the OR operation is not an exclusive or operation, so TRUE | TRUE equals TRUE as well.
var(data)*(n-1)/n
So, we can use the following simple calculation to retrieve the population variance from sample data. Since var() in R provides the sample variance, we can multiply var() with (n-1)/n to get the population variance. It will provide the same output as the following when calculated manually.
In R, missing values are represented by the symbol NA (not available).
A NAN value in R represents “NOT A NUMBER”, It is basically any numeric calculations with an undefined result, such as '0/0'. This exists only in vectors with numeric datatype. A NA value in R represents "NOT AVAILABLE". This can exist in any sort of numeric or character vectors.
The NaN values are referred to as the Not A Number in R. It is also called undefined or unrepresentable but it belongs to numeric data type for the values that are not numeric, especially in case of floating-point arithmetic. To remove rows from data frame in R that contains NaN, we can use the function na. omit.
The R Symbol ®
Usually, using ® means that your trademark is registered in a country. In some countries, however, its use is non-regulated and you can apply it even to unregistered trademarks (Canada is an example).
The R symbol indicates that this word, phrase, or logo is a registered trademark for the product or service. It must only be used in the case of registered trademarks and by the owner or licensee. It also must only be used in the regions in which you possess a valid trademark registration.
How do you type a subscript in R?
Subscripts and Superscripts
To indicate a subscript, use the underscore _ character. To indicate a superscript, use a single caret character ^ . Note: this can be confusing, because the R Markdown language delimits superscripts with two carets.
- arithmetic operators.
- relational operators.
- logical operators.
Work in R? != symbol is used for Not-Equal-To Operator in R Language. Not-Equal-To Operator takes two operands and returns a boolean value of TRUE if the two operands are not exactly equal to each other, or FALSE if they are exactly equal to each other.
- Increment and decrement operators.
- Bitwise operators.
- Assignment operators.
- Logical operators.
- Relational operators.
- Special operators.
- Conditional operators.
- Arithmetic Operators.
var() function in R Language computes the sample variance of a vector. It is the measure of how much value is away from the mean value.
R-squared (R2) is a statistical measure that represents the proportion of the variance for a dependent variable that's explained by an independent variable or variables in a regression model.
In R, sample variance is calculated with the var() function. In those rare cases where you need a population variance, use the population mean to calculate the sample variance and multiply the result by (n-1)/n; note that as sample size gets very large, sample variance converges on the population variance.
