# Programming with R: Part-1

R Codes
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 Code Purpose 2+2 Add 2 with 2 1:10 Get values 1 thru 10 201:300 Get values 201 thru 300 a=2 Assign value of a to 2. Note: This does not mean a is equal to 2. That purpose is met by a==2. a Know assigned value of a b=3 Assign value of b to 2. a*b Multiply a with b a^b a to the power b log(a) Log of a Note: By default log is natural i.e. with base e which we call ln. That is the code log(2) is tantamount to ln(2). Keep in mind that ln(2) is unavailable in R. log(2) Log of 2 exp(1) e to the power 1. ?log Get help about log. To get other help topics, type similarly like ?sum log (x, base=7) Usual format for value of log (x) with base 7 log (base=10, x=a) Detail format of log log (a,10) Shortcut format for log choose (12, 8) Number of possible combinations of taking 8 object out of 12. That is, it’s analogous to 12C8 gamma(5) Value of Γ5 that is, 4! factorial (8) 8! i.e. 8 factorial exp (2.3) e2.3 sqrt (8.4) Square root of 9.4 beta (2,3) B(a,b) = Γ(a)Γ(b)/Γ(a+b). round(2.34) Rounding round(2.34567, 4) Rounding up to 4 decimal pi 3.1416… i.e. value of π abs (-2) Absolute value of (-2) class (b) See the type of object b class (log) See class of log sqrt (beta(7,9)) Square root of this beta value log(17) +1 Same as code
Courtesy: Dr. Jafor Ahmed Khan
Profesor, Dept. of Statistics, Biostatistics & Informatics, University of Dhaka