R-MATLAB-IGOR Cheat Sheet

This is a short guide to translate commands in three different numerical analysis software packages: R, MATLAB and IGOR Pro. Equivalents are given for commands, gathered under a set of headings. This work is mainly by Vidar Bronken Gundersen and Ben Gallarda, see Credits for details.

If you can contribute to this cheat sheet (edits, corrections, more categories etc.), please use GitHub's fork/pull/propose changes facility. The fields with ? need attention.

Note that some commands use IGOR Pro 7 and are not compatible with IGOR Pro 6.3 or lower.

Basics and Terminology

Description	R	MATLAB	IGOR
Indexing	1-based	1-based	0-based
Case sEnSiTiVe	Yes	Yes	No
Scalar	Variable	Scalar	Variable
List of numbers	Vector	Vector	1D Wave equivalent to column vector
Matrix of numbers	Matrix	Matrix	2D Wave or Matrix
Higher dimensions	Yes	Yes	Yes Rows = p Columns = q Layers = r Chunks = s
Variables and number types	`int` `num` = Double `logi` Use `lubridate` `complex`	4 integer types Double ? Use `datenum` Complex number type	`Make/B a` or `Variable` or `NVAR` `Make/D a` or `Variable` or `NVAR` ? Date/Time Wave Complex number type
Text	`chr`	?	TextWave: `Make/T a` or `String` or `SVAR`
Mixed-type "matrix"	Yes Data Frame	Yes struct	Generally no Possible with `.id`

Help

Description	R	MATLAB	IGOR
Browse help interactively	`help.start()`	`doc`	`F1` Help > Igor Help Browser
Help on using help	`help()`	`help help` or `doc doc`	`DisplayHelpTopic "Help"`
Help for a function	`help(plot)` or `?plot`	`help plot`	Right-click function name "Help for function" or `⎇`+`⌘`+`F1`
Help for a toolbox/library package	`help`	`help splines` or `doc splines`
Demonstration examples	`demo()`	`demo`	File > Example Experiments
Example using a function	`example(plot)`		Example using a function

Searching available documentation

Description	R	MATLAB	IGOR
Search help files	`help.search('plot')`	`lookfor plot`	`F1` Help > Igor Help Browser
Find objects by partial name	`apropos('plot')`
List available packages	`library()`	`help`
Locate functions	`find(plot)`	`which plot`	Help > Command Help
List available methods for a function	`methods(plot)`

Using interactively

Description	R	MATLAB	IGOR
Start session	`Rgui`		File > New Experiment or `⌘`+`N`
Run code from file	`source('foo.R')`	`foo(.m)`	`FunctionName()`
Command history	`history()`		See History Area
Save command history	`savehistory(file=".Rhistory")`	`diary on [..] diary off`	`CreateHistoryCarbonCopy()`
End session	`q(save='no')`	`exit` or `quit`	`quit()` or `⌘`+`Q`

Operators

Description	R	MATLAB	IGOR
Help on operator syntax	`help(Syntax)`	`help -`	`DisplayHelpTopic "Operators"` or `DisplayHelpTopic "MatrixOP"`

Arithmetic operators

Description	R	MATLAB	IGOR
Assignment; defining a number	`a<-1; b<-2`	`a=1; b=2;`	`Variable a=1, b=2`
Addition	`a + b`	`a + b`	`a + b`
Subtraction	`a - b`	`a - b`	`a - b`
Multiplication	`a * b`	`a * b`	`a * b`
Division	`a / b`	`a / b`	`a / b`
Power, a^b	`a ^ b`	`a .^ b`	`a ^ b`
Remainder	`a %% b`	`rem(a,b)`	`mod(a,b)`
Integer division	`a %/% b`
Factorial, n!	`factorial(a)`	`factorial(a)`	`factorial(a)`

Relational operators

Description	R	MATLAB	IGOR
Equal	`a == b`	`a == b`	`a == b`
Less than	`a < b`	`a < b`	`a < b`
Greater than	`a > b`	`a > b`	`a > b`
Less than or equal	`a <= b`	`a <= b`	`a <= b`
Greater than or equal	`a >= b`	`a >= b`	`a >= b`
Not Equal	`a != b`	`a ~= b`	`a != b`

Logical operators

Description	R	MATLAB	IGOR
Short-circuit logical AND	`a && b`	`a && b`	`a && b`
Short-circuit logical OR	`a		b`
Element-wise logical AND	`a & b`	`a & b` or `and(a,b)`	`a & b`
Element-wise logical OR	`a	b`	`a
Logical EXCLUSIVE OR	`xor(a, b)`	`xor(a, b)`	`%^`
Logical NOT	`!a`	`~a` or `not(a)`	`!a`
True if any element is nonzero		`any(a)`
True if all elements are nonzero		`all(a)`

root and logarithm

Description	R	MATLAB	IGOR
Square root	`sqrt(a)`	`sqrt(a)`	`sqrt(a)`
Logarithm, base e (natural)	`log(a)`	`log(a)`	`ln(a)`
Logarithm, base 10	`log10(a)`	`log10(a)`	`log(a)`
Logarithm, base 2 (binary)	`log2(a)`	`log2(a)`	`log(a) / log(2)`
Exponential function	`exp(a)`	`exp(a)`	`exp(a)`

Round off

Description	R	MATLAB	IGOR
Round	`round(a)`	`round(a)`	`round(a)`
Round up	`ceil(a)`	`ceil(a)`	`ceil(a)`
Round down	`floor(a)`	`floor(a)`	`floor(a)`
Round towards zero		`fix(a)`	`trunc(a)`

Mathematical constants

Description	R	MATLAB	IGOR
π = 3.141592	`pi`	`pi`	`pi`
e = 2.718281	`exp(1)`	`exp(1)`	`e`

Missing values

Description	R	MATLAB	IGOR
Not a Number		`NaN`	`NaN`
Infinity, ∞		`Inf`	`inf`

Complex numbers

Description	R	MATLAB	IGOR
Imaginary unit	`1i`	`i`	`i`
A complex number, 3 + 4i	`z <- 3+4i`	`z = 3+4i`	`variable/c z = cmplx(3,4)`
Absolute value (modulus)	`abs(3+4i)` or `Mod(3+4i)`	`abs(z)`	`sqrt(magSqr(z)`
Real part	`Re(3+4i)`	`real(z)`	`real(z)`
Imaginary part	`Im(3+4i)`	`imag(z)`	`imag(z)`
Argument	`Arg(3+4i)`	`arg(z)`
Complex conjugate	`Conj(3+4i)`	`conj(z)`	`conj(z)`

Trigonometry

Description	R	MATLAB	IGOR
Arctangent, arctan(b/a)	`atan2(b,a)`	`atan(a,b)`	`atan2(b,a)`

Generate random numbers

Description	R	MATLAB	IGOR
Uniform distribution	`runif(10)`	`rand(1,10)`	`Make/N=10 wave0 = 0.5 + enoise(0.5)`
Uniform: Numbers between 2 and 7	`runif(10, min=2, max=7)`	`2+5*rand(1,10)`	`Make/N=10 wave0 = 2+ + abs(enoise(5))`
Uniform: 6,6 array	`matrix(runif(36),6)`	`rand(6)`	`Make/N=(6,6) wave0 = enoise(1)`
Normal distribution	`rnorm(100,0,1)`	`randn(100,1)`	`Make/N=100 wave0 = gnoise(1)`

Vectors

Description	R	MATLAB	IGOR
Row vector, 1 × n-matrix	`a <- c(2,3,4,5)`	`a=[2 3 4 5];`	`Make/N=4 a = {2, 3, 4, 5}`
Column vector, m × 1-matrix	`adash <- t(c(2,3,4,5))`	`adash=[2 3 4 5]';`	`Make/N=(1,4) adash = {2, 3, 4, 5}`

Sequences

Description	R	MATLAB	IGOR
1,2,3, … ,10	`seq(10)` or `1:10`	`1:10`	`make/N=10 a = p+1`
0.0,1.0,2.0, … ,9.0	`seq(0,length=10)`	`0:9`	`Make/N=10 a = p`
1,4,7,10	`seq(1,10,by=3)`	`1:3:10`	`Make/N=4 a = p*3+1`
10,9,8, … ,1	`seq(10,1)` or `10:1`	`10:-1:1`	`make/N=10 a = 10-p`
10,7,4,1	`seq(from=10,to=1,by=-3)`	`10:-3:1`	`Make/N=4 a = 10-(p*3)`
Linearly spaced vector of n=7 points	`seq(1,10,length=7)`	`linspace(1,10,7)`	`Make/N=2 a = {1,10}` `Interpolate2/T=1/N=7/Y=a_L a`
Reverse	`rev(a)`	`reverse(a)`	`Reverse a`
Set all values to same scalar value		`a(:) = 3`	`a = 3`

Concatenation (vectors)

Description	R	MATLAB	IGOR
Concatenate two vectors	`c(a,a)`	`[a a]`	`Concatenate {a,a}, b`
	`c(1:4,a)`	`[1:4 a]`	`Make/N=4 b = 1 + p` `Concatenate {b,a}, c`

Repeating

Description	R	MATLAB	IGOR
1 2 3, 1 2 3	`rep(a,times=2)`	`[a a]`	`Concatenate/NP {a,a}, b`
1 1 1, 2 2 2, 3 3 3	`rep(a,each=3)`		`Concatenate {a,a,a},b` `MatrixTranspose b` `Redimension/N=9 b`
1, 2 2, 3 3 3	`rep(a,a)`

Miss those elements out

Description	R	MATLAB	IGOR
miss the first element	`a[-1]`	`a(2:end)`	`a[1,*]`
miss the tenth element	`a[-10]`	`a([1:9])`	`a[0,numpnts(a)-2]`
miss 1,4,7, …	`a[-seq(1,50,3)]`		`a[0,*;3]`
last element		`a(end)`	`a[numpnts(a)-1]`
last two elements		`a(end-1:end)`	`a[numpnts(a)-2,*]`

Maximum and minimum

Description	R	MATLAB	IGOR
pairwise max	`pmax(a,b)`	`max(a,b)`	`max(a,b)`
max of all values in two vectors	`max(a,b)`	`max([a b])`	`max(wavemax(a),wavemax(b))`
	`v <- max(a) ; i <- which.max(a)`	`[v,i] = max(a)`	`WaveStats a` v = V_max, i = V_maxRowLoc

Vector multiplication

Description	R	MATLAB	IGOR
Multiply two vectors	`a*a`	`a.*a`	`MatrixOp b = a * a`
Vector dot product, u ⋅ v		`dot(u,v)`	`MatrixOp b = u . v`

Matrices

Description	R	MATLAB	IGOR
Define a matrix	`rbind(c(2,3),c(4,5))` `array(c(2,3,4,5), dim=c(2,2))`	`a = [2 3;4 5]`	`Make/N=(2,2) a = {{2,4},{3,5}}`

Concatenation (matrices); rbind and cbind

Description	R	MATLAB	IGOR
Bind rows	`rbind(a,b)`	`[a ; b]`	`Concatenate/NP=1 {a,b}, c`
Bind columns	`cbind(a,b)`	`[a , b]`	`Concatenate/NP=0 {a,b}, c`
Concatenate matrices into one vector		`[a(:), b(:)]`	?
Bind rows (from vectors)	`rbind(1:4,1:4)`	`[1:4 ; 1:4]`	`Make/N=(2,4) a = 1 + q`
Bind columns (from vectors)	`cbind(1:4,1:4)`	`[1:4 ; 1:4]'`	`Make/N=(4,2) a = 1 + p`

Array creation

Description	R	MATLAB	IGOR
0 filled array	`matrix(0,3,5)` or `array(0,c(3,5))`	`zeros(3,5)`	`Make/N=(3,5) a = 0`
1 filled array	`matrix(1,3,5)` or `array(1,c(3,5))`	`ones(3,5)`	`Make/N=(3,5) a = 1`
Any number filled array	`matrix(9,3,5)` or `array(9,c(3,5))`	`ones(3,5)*9`	`Make/N=(3,5) a = 9`
Identity matrix	`diag(1,3)`	`eye(3)`	Identity matrix
Diagonal	`diag(c(4,5,6))`	`diag([4 5 6])`	`Make/N=(3,3) a = 4+p` `MatrixOp b = diagonal(a)`
Magic squares; Lo Shu		`magic(3)`	?

Reshape and flatten matrices

Description	R	MATLAB	IGOR
Reshaping (rows first)	`matrix(1:6,nrow=3,byrow=T)`	`reshape(1:6,3,2)';`	`Make/N=6 a = 1 + p` `Redimension/N=(2,3) a`
Reshaping (columns first)	`matrix(1:6,nrow=2)` `array(1:6,c(2,3))`	`reshape(1:6,2,3);`	As above, then `MatrixTranspose a`
Flatten to vector (by rows, like comics)	`as.vector(t(a))`	`a'(:)`	`WaveTranspose a` `Redimension/N=(numpnts(a)) a`
Flatten to vector (by columns)	`as.vector(a)`	`a(:)`	`Redimension/N=(numpnts(a)) a`
Flatten upper triangle (by columns)	`a[row(a) <= col(a)]`	`vech(a)`	?

Shared data (slicing)

Description	R	MATLAB	IGOR
Copy of a	`b = a`	`b = a`	`Duplicate a, b`

Indexing and accessing elements (Python: slicing)

Description	R	MATLAB	IGOR
Input is a 3,4 array	`a <- rbind(c(11, 12, 13, 14),` `c(21, 22, 23, 24),` `c(31, 32, 33, 34))`	`a = [ 11 12 13 14 ...` `21 22 23 24 ...` `31 32 33 34 ]`	`Make/N=(4,3) a = {{11,12,13,14},{21,22,23,24},{31,32,33,34}}` `MatrixTranspose a`
Element 2,3 (row,col)	`a[2,3]`	`a(2,3)`	`a[1][2]`
First row	`a[1,]`	`a(1,:)`	`a[0][]`
First column	`a[,1]`	`a(:,1)`	`a[][0]`
Array as indices		`a([1 3],[1 4]);`	?
All, except first row	`a[-1,]`	`a(2:end,:)`	`a[1,*][]`
Last two rows		`a(end-1:end,:)`	`a[dimsize(a,0)-2,][]`
Strides: Every other row		`a(1:2:end,:)`	`a[0,*;2][]`
All, except row,column (2,3)	`a[-2,-3]`		?
Remove one column	`a[,-2]`	`a(:,[1 3 4])`	`DeletePoints/M=1 0,1,a`

Assignment

Description	R	MATLAB	IGOR
	`a[,1] <- 99`	`a(:,1) = 99`	`a[][1] = 99`
	`a[,1] <- c(99,98,97)`	`a(:,1) = [99 98 97]'`	`a[][1] = {99,98,97}` or `a[][1] = 99 - p`
Clipping: Replace all elements over 90	`a[a>90] <- 90`	`a(a>90) = 90;`	`a = (a[p][q] > 90) ? 90 : a[p][q]`

Transpose and inverse

Description	R	MATLAB	IGOR
Transpose	`t(a)`	`a'`	`MatrixTranspose a`
Non-conjugate transpose		`a.'` or `transpose(a)`	`MatrixTranspose/H a`
Determinant	`det(a)`	`det(a)`	`MatrixDet a` or `MatrixOp b = det(a)`
Inverse	`solve(a)`	`inv(a)`	`MatrixInverse a`
Pseudo-inverse	`ginv(a)`	`pinv(a)`	`MatrixInverse/P a`
Norms		`norm(a)`	`norm(a)`
Eigenvalues	`eigen(a)$values`	`eig(a)`	`MatrixEigenV a`
Singular values	`svd(a)$d`	`svd(a)`	`MatrixSVD a`
Cholesky factorization		`chol(a)`	`MatrixOp chol(a)`
Eigenvectors	`eigen(a)$vectors`	`[v,l] = eig(a)`	`MatrixEigenV a`
Rank	`rank(a)`	`rank(a)`	`MatrixRank(a)`

Sum

Description	R	MATLAB	IGOR
Sum of each column	`apply(a,2,sum)`	`sum(a)`	`MatrixOp b = sumCols(a)`
Sum of each row	`apply(a,1,sum)`	`sum(a')`	`MatrixOp b = sumRows(a)`
Sum of all elements	`sum(a)`	`sum(sum(a))`	`Sum(a)`
Cumulative sum (columns)	`apply(a,2,cumsum)`	`cumsum(a)`	`MatrixOp b = sumCols(a)` `Integrate/DIM=1 b`

Sorting

Description	R	MATLAB	IGOR
	`a <- rbind(c(4,3,2),c(2,8,6),c(1,4,7))`	`a = [ 4 3 2 ; 2 8 6 ; 1 4 7 ]`	`Make/N=(3,3) a = {{4,2,1},{3,8,4},{2,6,7}}`
Flat and sorted	`t(sort(a))`	`sort(a(:))`	`Redimension/N=9 a` `Sort a,a`
Sort each column	`apply(a,2,sort)`	`sort(a)`	`SortColumns keywaves={a},sortwaves={a}`
Sort each row	`t(apply(a,1,sort))`	`sort(a')'`	`SortColumns` following `MatrixTranspose`
Sort rows (by first row)		`sortrows(a,1)`	?
Sort, return indices	`order(a)`		`MakeIndex a,b` ?

Maximum and minimum

Description	R	MATLAB	IGOR
max in each column	`apply(a,2,max)`	`max(a)`	`MatrixOp b=maxCols(a)`
max in each row	`apply(a,1,max)`	`max(a')`	`MatrixOp b=a^t` `MatrixOp c=maxCols(b)`
max in array	`max(a)`	`max(max(a))`	`MatrixOp b=maxVal(a)` or `WaveStats a`
return indices, i	`i <- apply(a,1,which.max)`	`[v i] = max(a)`	`WaveStats a` V_maxRowLoc V_maxColLoc
pairwise max	`pmax(b,c)`	`max(b,c)`	`max(b,c)`
	`apply(a,2,cummax)`	`cummax(a)`	`max(sum(b),sum(c))`

Matrix manipulation

Description	R	MATLAB	IGOR
Flip left-right	`a[,4:1]`	`fliplr(a)`	`MatrixOp b=reverseRows(a)`
Flip up-down	`a[3:1,]`	`flipud(a)`	`MatrixOp b=reverseCols(a)`
Rotate 90 degrees		`rot90(a)`	`MatrixOp b=a^t`
Repeat matrix: [ a a a ; a a a ]	`kronecker(matrix(1,2,3),a)`	`repmat(a,2,3)`	`Concatenate/NP=1 {a,a,a},b` `Concatenate/NP=0 {b,b},c`
Triangular, upper	`a[lower.tri(a)] <- 0`	`triu(a)`	?
Triangular, lower	`a[upper.tri(a)] <- 0`	`tril(a)`	?

Equivalents to “size”

Description	R	MATLAB	IGOR
Matrix dimensions	`dim(a)`	`size(a)`	`WaveInfo(a)` or see Data Browser
Number of columns	`ncol(a)`	`size(a,2)` or `length(a)`	`dimsize(a,1)`
Number of elements	`prod(dim(a))`	`length(a(:))`	`numpnts(a)`
Number of dimensions		`ndims(a)`	`WaveDims(a)`
Number of bytes used in memory	`object.size(a)`		`WaveInfo(a)` or see Data Browser

Matrix- and elementwise- multiplication

Description	R	MATLAB	IGOR
Elementwise operations	`a * b`	`a .* b`	`MatrixOp c = a * b`
Matrix product (dot product)	`a %*% b`	`a * b`	`MatrixOp c = a . b`
Outer product	`outer(a,b)` or `a %o% b`	`b * a`	`MatrixMultiply a,b`
Cross product	`crossprod(a,b)` or `t(a) %*% b`		`Cross a,b`
Kronecker product	`kronecker(a,b)`	`kron(a,b)`	`MatrixOp c = tensorProduct(a,b)`
Matrix division, b ⋅ a⁻¹		`a / b`	`MatrixOp c = a / b`
Left matrix division, b⁻¹ ⋅ a (solve linear equations)	`solve(a,b)`	`a \ b`	?

Find; conditional indexing

Description	R	MATLAB	IGOR
Non-zero elements, indices	`which(a != 0)`	`find(a)`	`Duplicate a,b` `b = (a != 0) ? p : NaN` `WaveTransform zapnans b`
Non-zero elements, array indices	`which(a != 0, arr.ind=T)`	`[i j] = find(a)`	Write a loop
Vector of non-zero values	`ij <- which(a != 0, arr.ind=T); v <- a[ij]`	`[i j v] = find(a)`	`a = (a[p][q] != 0) ? a[p][q] : NaN` `Redimension/N=(numpnts(a)) a` `WaveTransform a`
Condition, indices	`which(a>5.5)`	`find(a>5.5)`	`Duplicate a,b` `b = a[p][q] > 5.5 ? p : NaN` `WaveTransform zapnans b`
Return values	`ij <- which(a>5.5, arr.ind=T); v <- a[ij]`		`Duplicate a,b` `b = a[p][q] > 5.5 ? a[p][q] : NaN` `WaveTransform zapnans b`
Zero out elements above 5.5		`a .* (a>5.5)`	`a = (a[p][q] > 5.5) ? 0 : a[p][q]`

Multi-way arrays

Description	R	MATLAB	IGOR
Define a 3-way array		`a = cat(3, [1 2; 1 2],[3 4; 3 4]);`	`Make/N=(2,2,2) a={{{1,1},{2,2}},{{3,3},{4,4}}}`
		`a(1,:,:)`	`Make/N=(1,2,2) b` `b[0][][]=a[p][q][r]`

File input and output

Description	R	MATLAB	IGOR
Reading from a file (2d)	`f <- read.table("data.txt")`	`f = load('data.txt')`	Data > Load Waves...
Reading fram a CSV file (2d)	`f <- read.table(file="data.csv", sep=";")`	`x = dlmread('data.csv', ';')`	`LoadWave/J/M/D/N=wave/O/K=0 "data.csv"`
Writing to a file (2d)	`write(f,file="data.txt")`	`save -ascii data.txt f`	`Save/J/M="\n"/W f as "data.txt"`

###Plotting

Basic x-y plots

Description	R	MATLAB	IGOR
1d line plot	`plot(a, type="l")`	`plot(a)`	`display a`
2d scatter plot	`plot(x[,1],x[,2])`	`plot(x(:,1),x(:,2),'o')`	`display a vs b`
Two graphs in one plot		`plot(x1,y1, x2,y2)`	`display a, b` or `display a1 vs b1, a2 vs b2`
Overplotting: Add new plots to current	`plot(x1,y1)` `matplot(x2,y2,add=T)`	`plot(x1,y1)` `hold on` `plot(x2,y2)`	`display a; AppendToGraph b`
subplots		`subplot(211)`	Add to procedure window `#include <InsertSubwindowInGraph>`
Plotting symbols and color	`plot(x,y,type="b",col="red")`	`plot(x,y,'ro-')`	Double-click trace on graph

Axes and titles

Description	R	MATLAB	IGOR
Turn on grid lines	`grid()`	`grid on`	`ModifyGraph grid=1`
1:1 aspect ratio	`plot(c(1:10,10:1), asp=1)`	`axis equal`	`ModifyGraph width={Plan,1,bottom,left}`
Set axes manually	`plot(x,y, xlim=c(0,10), ylim=c(0,5))`	`axis([ 0 10 0 5 ])`	`SetAxis left 0,5` `SetAxis bottom 0,10`
Axis labels and titles	`plot(1:10, main="title",` `xlab="x-axis", ylab="y-axis")`	`title('title')` `xlabel('x-axis')` `ylabel('y-axis')`	`Label left "y-axis"` `Label bottom "x-axis"`

Log plots

Description	R	MATLAB	IGOR
logarithmic y-axis	`plot(x,y, log="y")`	`semilogy(a)`	`ModifyGraph log(left)=1`
logarithmic x-axis	`plot(x,y, log="x")`	`semilogx(a)`	`ModifyGraph log(bottom)=1`
logarithmic x and y axes	`plot(x,y, log="xy")`	`loglog(a)`	`ModifyGraph log=1`

Filled plots and bar plots

Description	R	MATLAB	IGOR
Filled plot	`plot(t,s, type="n", xlab="", ylab="")` `polygon(t,s, col="lightblue")` `polygon(t,c, col="lightgreen")`	`fill(t,s,'b', t,c,'g')`	`Display a` `ModifyGraph mode=7`
Stem-and-Leaf plot	`stem(x[,3])`		?

Functions

Description	R	MATLAB	IGOR
Defining functions	`f <- function(x) sin(x/3) - cos(x/5)`	`f = inline('sin(x/3) - cos(x/5)')`	`Make a = sin(x/3) - cos(x/5` Default wave length is 128
Plot a function for given range	`plot(f, xlim=c(0,40), type='p')`	`ezplot(f,[0,40])` `fplot('sin(x/3) - cos(x/5)',[0,40])`	`Display a[0,40]`

Polar plots

Description	R	MATLAB	IGOR
		`theta = 0:.001:2pi;` `r = sin(2theta);`
Polar plot	See `polar.plot`	`polar(theta, rho)`	`#include <New Polar Graphs>` in procedure window

Histogram plots

R	MATLAB	IGOR
`hist(rnorm(1000))`	`hist(randn(1000,1))`	`Make/O/N=1000 a=gnoise(1)` `Make/N=0/O a_Hist` `Histogram/B=3 a,a_Hist` `Display a_Hist`
`hist(rnorm(1000), breaks= -4:4)`	`hist(randn(1000,1), -4:4)`	As above except `Make/N=8/O a_Hist` `Histogram/B={-4,1,8} a,a_Hist`
`hist(rnorm(1000),` `breaks=c(seq(-5,0,0.25),` `seq(0.5,5,0.5)), freq=F)`		Concatenate two sub-histograms
`plot(apply(a,1,sort),type="l")`	`plot(sort(a))`	?

3d data

Contour and image plots

Description	R	MATLAB	IGOR
Contour plot	`contour(z)`	`contour(z)`	`Display; AppendMatrixContour z`
Filled contour plot	`filled.contour(x,y,z,` `nlevels=7, color=gray.colors)`	`contourf(z); colormap(gray)`	`Display; AppendMatrixContour z` `ModifyContour z fill=1`
Plot image data	`image(z, col=gray.colors(256))`	`image(z)` `colormap(gray)`	`newimage z` or `display;appendimage z`
Direction field vectors		`quiver()`	`DisplayHelpTopic "ModifyGraph for Traces"`

Perspective plots of surfaces over the x-y plane

Description	R	MATLAB	IGOR
	`f <- function(x,y) x*exp(-x^2-y^2)` `n <- seq(-2,2, length=40)` `z <- outer(n,n,f)`	`n=-2:.1:2;` `[x,y] = meshgrid(n,n);` `z=x.*exp(-x.^2-y.^2);`
Mesh plot	`persp(x,y,z,` `theta=30, phi=30, expand=0.6,` `ticktype='detailed')`	`mesh(z)`	`ImageInterpolate/CMSH voronoi a` `AppendToGizmo surface=root:a,name=surface0` `ModifyGizmo ModifyObject=surface0,objectType=surface,property={ fillMode,3}`
Surface plot	`persp(x,y,z,` `theta=30, phi=30, expand=0.6,` `col='lightblue', shade=0.75, ltheta=120,` `ticktype='detailed')`	`surf(x,y,z)` or `surfl(x,y,z)`	`Concatenate {x,y,z},wave3D` `NewGizmo` `AppendToGizmo Scatter=root:wave3d,name=surface0`

Scatter (cloud) plots

Description	R	MATLAB	IGOR
3d scatter plot	`cloud(z~x*y)`	`plot3(x,y,z,'k+')`	`Concatenate {x,y,z},wave3D` `NewGizmo` `AppendToGizmo Scatter=root:wave3d,name=scatter0`

Save plot to a graphics file

Description	R	MATLAB	IGOR
PostScript	`postscript(file="foo.eps")` `plot(1:10)` `dev.off()`	`plot(1:10)` `print -depsc2 foo.eps`	`SavePict/E=-3 as "foo.eps"`
PDF	`pdf(file='foo.pdf')`		`SavePict/E=-2 as "foo.pdf"`
SVG (vector graphics for www)	`devSVG(file='foo.svg')`		`SavePict/E=-9 as "foo.svg"`
PNG (raster graphics)	`png(filename = "Rplot%03d.png"`	`print -dpng foo.png`	`SavePict/E=-5 as "foo.png"`

Data analysis

Set membership operators

Description	R	MATLAB	IGOR
Create sets	`a <- c(1,2,2,5,2)` `b <- c(2,3,4)`	`a = [ 1 2 2 5 2 ];` `b = [ 2 3 4 ];`	Create sets
Set unique	`unique(a)`	`unique(a)`	`FindDuplicates/RN=c a`
Set union	`union(a,b)`	`union(a,b)`	? via loop
Set intersection	`intersect(a,b)`	`intersect(a,b)`	? via loop
Set difference	`setdiff(a,b)`	`setdiff(a,b)`	? via loop
Set exclusion	`setdiff(union(a,b),intersect(a,b))`	`setxor(a,b)`	? via loop
True for set member	`is.element(2,a)` or `2 %in% a`	`ismember(2,a)`	`FindValue/I=2 a`

Statistics

Description	R	MATLAB	IGOR
Average	`apply(a,2,mean)`	`mean(a)`	`mean(a)` Note:`WaveStats a` or `ImageStats a` gives many statistics
Median	`apply(a,2,median)`	`median(a)`	`median(a)` or `statsmedian(a)`
Standard deviation	`apply(a,2,sd)`	`std(a)`	`WaveStats a`
Variance	`apply(a,2,var)`	`var(a)`	`Variance(a)`
Correlation coefficient	`cor(x,y)`	`corr(x,y)`	`StatsCorrelation x,y` or `Correlate x,y`
Covariance	`cov(x,y)`	`cov(x,y)`	`MatrixCorr/COV x,y`

Interpolation and regression

Description	R	MATLAB	IGOR
Straight line fit	`z <- lm(y~x)` `plot(x,y)` `abline(z)`	`z = polyval(polyfit(x,y,1),x)` `plot(x,y,'o', x,z ,'-')`	`CurveFit line b /X=a /D`
Linear least squares y = a__x + b	`solve(a,b)`	`a = x\y`	`MatrixLLS a,b`
Polynomial fit		`polyfit(x,y,3)`	`CurveFit Poly2D 3 a /Ywave=b

Non-linear methods

Polynomials, root finding

Description	R	MATLAB	IGOR
Find zeros of polynomial	`polyroot(c(1,-1,-1))`	`roots([1 -1 -1])`	`Make a={1,-1,-1}` `FindRoots/P=a`
Find a zero near x = 1		`f = inline('1/x - (x-1)')` `fzero(f,1)`	?
Solve symbolic equations		`solve('1/x = x-1')`	?
Evaluate polynomial		`polyval([1 2 1 2],1:10)`	?

Differential equations

Description	R	MATLAB	IGOR
Discrete difference function and approximate derivative		`diff(a)`	?
Solve differential equations			`Differentiate a` ?

Fourier analysis

Description	R	MATLAB	IGOR
Fast fourier transform	`fft(a)`	`fft(a)`	`FFT a`
Inverse fourier transform	`fft(a, inverse=TRUE)`	`ifft(a)`	`IFFT a`

Symbolic algebra; calculus

Description	R	MATLAB	IGOR
Factorization	`FUN <- function(x) {` `x <- as.integer(x)` `div <- seq_len(abs(x))` `factors <- div[x %% div == 0L]` `factors <- list(neg = -factors, pos = factors)` `return(factors)` `}`	`factor()`	Only `PrimeFactors a`

Programming

Description	R	MATLAB	IGOR
Script file extension	`.R`	`.m`	`.ipf`
Comment symbol (rest of line)	`#`	`%`	`//`
Import library functions	`library(RSvgDevice)`	`% must be in MATLABPATH`	`#include "Name"` without .ipf extension. Must be in User Procedures Folder
Eval	`string <- "a <- 234"` `eval(parse(text=string))`	`string='a=234';` `eval(string)`	`String a = "234"` `str2num(a)`

Loops

Description	R	MATLAB	IGOR
for-statement	`for(i in 1:5) print(i)`	`for i=1:5; disp(i); end`
Multiline for statements	`for(i in 1:5) {` `print(i)` `print(i*2)` `}`	`for i=1:5` `disp(i)` `disp(i*2)` `end`	`for(i=0;i<10;i+=1)` `print i` `endfor`

Conditionals

Description	R	MATLAB	IGOR
if-statement	`if (1>0) a <- 100`	`if 1>0 a=100; end`	`if (1 > 0)` `a = 100` `endif`
if-else-statement		`if 1>0 a=100; else a=0; end`	`if (1 < 0)` `a = 100` `else` `a=0 endif`
Ternary operator (if?true:false)	`ifelse(a>0,a,0)`		`a = a[] > 0 ? a[p] : 0`

Debugging

Description	R	MATLAB	IGOR
Most recent evaluated expression	`.Last.value`	`ans`	Arrow up
List variables loaded into memory	`objects()`	`whos` or `who`	Data > Data Browser
Clear variable x from memory	`rm(x)`	`clear x` or `clear [all]`	`KillVariables` or `KillStrings`or`KillWaves`
Print	`print(a)`	`disp(a)`	`Print a`

Working directory and OS

Description	R	MATLAB	IGOR
List files in directory	`list.files()` or `dir()`	`dir` or `ls`	Data > Data Browser
List script files in directory	`list.files(pattern="\.r$")`	`what`	Window > Procedure Window
Displays the current working directory	`getwd()`	`pwd`	`GetDataFolder(0)`
Change working directory	`setwd('foo')`	`cd foo`	`SetDataFolder $expDataFolderName`
Invoke a System Command	`system("notepad")`	`!notepad`	`Execute "command"`

##Credits

An edited version with added IgorPro commands was made by Ben Gallarda

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R-MATLAB-IGOR Cheat Sheet

Basics and Terminology

Help

Searching available documentation

Using interactively

Operators

Arithmetic operators

Relational operators

Logical operators

root and logarithm

Round off

Mathematical constants

Missing values

Complex numbers

Trigonometry

Generate random numbers

Vectors

Sequences

Concatenation (vectors)

Repeating

Miss those elements out

Maximum and minimum

Vector multiplication

Matrices

Concatenation (matrices); rbind and cbind

Array creation

Reshape and flatten matrices

Shared data (slicing)

Indexing and accessing elements (Python: slicing)

Assignment

Transpose and inverse

Sum

Sorting

Maximum and minimum

Matrix manipulation

Equivalents to “size”

Matrix- and elementwise- multiplication

Find; conditional indexing

Multi-way arrays

File input and output

Basic x-y plots

Axes and titles

Log plots

Filled plots and bar plots

Functions

Polar plots

Histogram plots

3d data

Contour and image plots

Perspective plots of surfaces over the x-y plane

Scatter (cloud) plots

Save plot to a graphics file

Data analysis

Set membership operators

Statistics

Interpolation and regression

Non-linear methods

Polynomials, root finding

Differential equations

Fourier analysis

Symbolic algebra; calculus

Programming

Loops

Conditionals

Debugging

Working directory and OS

About

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