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This chapter introduces simple operations in R. ### Assignment In most languages, the assignment operator is **=**, but R is a mathematical language, so the assignment symbol is similar to the pseudocode in our math textbooks, a left arrow <- : ## Example a <-123 b <-456 print(a + b) The execution result of the above code: 579 This assignment symbol is a formal advantage and operational disadvantage of R: formally more suitable for mathematicians, since not all mathematicians are accustomed to using **=** as the assignment operator. Operationally, the 1+2*3 7 >(1+2)*3 9 >3/4 0.75 >3.4-1.2 2.2 >1-4*0.5^3 0.5 >8/3%%2 8 >8/4%%2 Inf >3%%2^2 3 >10/3%/%2 10 ### Relational Operators The following table lists the relational operators supported by R. Relational operators compare two vectors, comparing each element of the first vector with the second vector, and return a boolean value. | Operator | Description | | --- | --- | | > | Check if each element of the first vector is greater than the corresponding element of the second vector. | | = | Check if each element of the first vector is greater than or equal to the corresponding element of the second vector. | | <= | Check if each element of the first vector is less than or equal to the corresponding element of the second vector. | ## Example v <-c(2,4,6,9) tt) print(v =t) print(v<=t) The execution result of the above code: TRUE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE TRUE FALSE TRUE TRUE FALSE TRUE FALSE TRUE TRUE FALSE TRUE FALSE TRUE TRUE TRUE ### Logical Operators The following table lists the logical operators supported by R, which can be used for numeric, logical, and complex type vectors. Non-zero numbers (positive or negative) are all TRUE. Logical operators compare two vectors, comparing each element of the first vector with the second vector, and return a boolean value. | Operator | Description | | --- | --- | | & | Element-wise logical AND operator, combines each element of the first vector with the corresponding element of the second vector. If both elements are TRUE, the result is TRUE, otherwise FALSE. | | ｜ | Element-wise logical OR operator, combines each element of the first vector with the corresponding element of the second vector. If either element is TRUE, the result is TRUE; if both are FALSE, it returns FALSE. | | ! | Logical NOT operator, returns the opposite logical value of each element in the vector. If the element is TRUE, it returns FALSE; if the element is FALSE, it returns TRUE. | | && | Logical AND operator, only judges the first element of the two vectors. If both elements are TRUE, the result is TRUE, otherwise FALSE. | | || | Logical OR operator, only judges the first element of the two vectors. If either element is TRUE, the result is TRUE; if both are FALSE, it returns FALSE. | ## Example v <-c(3,1,TRUE,2+3i) t<-c(4,1,FALSE,2+3i) print(v&t) print(v|t) print(!v) # &&, || only compare the first element v <-c(3,0,TRUE,2+2i) t<-c(1,3,TRUE,2+3i) print(v&&t) v <-c(0,0,TRUE,2+2i) t<-c(0,3,TRUE,2+3i) print(v||t) The execution result of the above code: TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE FALSE FALSE FALSE FALSE TRUE FALSE ### Assignment Operators R variables can be assigned using left, right, or equal operators. The following table lists the assignment operators supported by R. | Operator | Description | | --- | --- | | <− = < −>> | Assign to the right. | ## Example # Assign to the left v1 <-c(3,1,TRUE,"tutorial") v2 <<-c(3,1,TRUE,"tutorial") v3 =c(3,1,TRUE,"tutorial") print(v1) print(v2) print(v3) #