命令

目的/作用

clc

清除命令窗口。

clear

從內存中刪除變量。

exist

檢查存在的文件或變量。

global

聲明變量為全局。

help

搜索幫助主題。

lookfor

搜索幫助關鍵字條目。

quit

停止MATLAB。

who

列出當前變量。（很好很強大，你值得擁有）

whos

列出當前變量（長顯示）。

命令

目的/作用

cd

改變當前目錄。

date

顯示當前日期。

delete

刪除一個文件。

diary

日記文件記錄開/關切換。

dir

列出當前目錄中的所有文件。

load

負載工作區從一個文件中的變量。

path

顯示搜索路徑。

pwd

顯示當前目錄。

save

保存在一個文件中的工作區變量。

type

顯示一個文件的??內容。

what

列出所有MATLAB文件在當前目錄中。

wklread

讀取.wk1電子表格文件。

語句

描述

if ... end statement

An if ... end statement consists of a boolean expression followed by one or more statements.

if...else...end statement

An if statement can be followed by an optional else statement, which executes when the boolean expression is false.

If... elseif...elseif...else...end statements

An if statement can be followed by an (or more) optional elseif...and an else statement, which is very useful to test various condition.

nested if statements

You can use one if or elseif statement inside another if or elseif statement(s).

switch statement

A switch statement allows a variable to be tested for equality against a list of values.

nested switch statements

You can use one swicth statement inside another switch statement(s).

while 循環

一個給定的條件為真時重復語句或語句組。測試條件才執行循環體。

for 循環

執行的語句序列多次縮寫管理循環變量的代碼。

nested 循環

可以使用一個或多個環路內任何另一個循環。

控制語句

描述

break 語句

終止循環語句，將執行的語句緊隨循環。

continue 語句

導致循環，跳過它的身體的其余部分，並立即重新再次測試前的狀況。

運算符

描述

+

加法或一元加號。A + B將A和B。 A和B必須具有相同的尺寸，除非一個人是一個標量。一個標量，可以被添加到任何大小的矩陣。

-

Subtraction or unary minus. A-B subtracts B from A. A and B must have the same size, unless one is a scalar. A scalar can be subtracted from a matrix of any size.

*

Matrix multiplication. C = A*B is the linear algebraic product of the matrices A and B. More precisely,

For nonscalar A and B, the number of columns of A must equal the number of rows of B. A scalar can multiply a matrix of any size.

.*

Array multiplication. A.*B is the element-by-element product of the arrays A and B. A and B must have the same size, unless one of them is a scalar.

/

Slash or matrix right division. B/A is roughly the same as B*inv(A). More precisely, B/A = (A‘B‘)‘.

./

Array right division. A./B is the matrix with elements A(i,j)/B(i,j). A and B must have the same size, unless one of them is a scalar.

Backslash or matrix left division. If A is a square matrix, AB is roughly the same as inv(A)*B, except it is computed in a different way. If A is an n-by-n matrix and B is a column vector with n components, or a matrix with several such columns, then X = AB is the solution to the equation AX = B. A warning message is displayed if A is badly scaled or nearly singular.

.

Array left division. A.B is the matrix with elements B(i,j)/A(i,j). A and B must have the same size, unless one of them is a scalar.

^

Matrix power. X^p is X to the power p, if p is a scalar. If p is an integer, the power is computed by repeated squaring. If the integer is negative, X is inverted first. For other values of p, the calculation involves eigenvalues and eigenvectors, such that if [V,D] = eig(X), then X^p = V*D.^p/V.

.^

Array power. A.^B is the matrix with elements A(i,j) to the B(i,j) power. A and B must have the same size, unless one of them is a scalar.

‘

Matrix transpose. A‘ is the linear algebraic transpose of A. For complex matrices, this is the complex conjugate transpose.

.‘

Array transpose. A.‘ is the array transpose of A. For complex matrices, this does not involve conjugation.

函數

描述

uplus(a)

Unary plus; increments by the amount a

plus (a,b)

Plus; returns a + b

uminus(a)

Unary minus; decrements by the amount a

minus(a, b)

Minus; returns a - b

times(a, b)

Array multiply; returns a.*b

mtimes(a, b)

Matrix multiplication; returns a* b

rdivide(a, b)

Right array division; returns a ./ b

ldivide(a, b)

Left array division; returns a. b

mrdivide(A, B)

Solve systems of linear equations xA = B for x

mldivide(A, B)

Solve systems of linear equations Ax = B for x

power(a, b)

Array power; returns a.^b

mpower(a, b)

Matrix power; returns a ^ b

cumprod(A)

Cumulative product; returns an array the same size as the array A containing the cumulative product.

• If A is a vector, then cumprod(A) returns a vector containing the cumulative product of the elements of A.
• If A is a matrix, then cumprod(A) returns a matrix containing the cumulative products for each column of A.
• If A is a multidimensional array, then cumprod(A) acts along the first nonsingleton dimension.

cumprod(A, dim)

Returns the cumulative product along dimension dim.

cumsum(A)

Cumulative sum; returns an array A containing the cumulative sum.

• If A is a vector, then cumsum(A) returns a vector containing the cumulative sum of the elements of A.
• If A is a matrix, then cumsum(A) returns a matrix containing the cumulative sums for each column of A.
• If A is a multidimensional array, then cumsum(A) acts along the first nonsingleton dimension.

cumsum(A, dim)

returns the cumulative sum of the elements along dimension dim.

diff(X)

Differences and approximate derivatives; calculates differences between adjacent elements of X.

• If X is a vector, then diff(X) returns a vector, one element shorter than X, of differences between adjacent elements: [X(2)-X(1) X(3)-X(2) ... X(n)-X(n-1)]
• If X is a matrix, then diff(X) returns a matrix of row differences: [X(2:m,:)-X(1:m-1,:)]

diff(X,n)

Applies diff recursively n times, resulting in the nth difference.

diff(X,n,dim)

It is the nth difference function calculated along the dimension specified by scalar dim. If order n equals or exceeds the length of dimension dim, diff returns an empty array.

prod(A)

Product of array elements; returns the product of the array elements of A.

• If A is a vector, then prod(A) returns the product of the elements.
• If A is a nonempty matrix, then prod(A) treats the columns of A as vectors and returns a row vector of the products of each column.
• If A is an empty 0-by-0 matrix, prod(A) returns 1.
• If A is a multidimensional array, then prod(A) acts along the first nonsingleton dimension and returns an array of products. The size of this dimension reduces to 1 while the sizes of all other dimensions remain the same.

The prod function computes and returns B as single if the input, A, is single. For all other numeric and logical data types, prod computes and returns B as double

prod(A,dim)

Returns the products along dimension dim. For example, if A is a matrix, prod(A,2) is a column vector containing the products of each row.

prod(___,datatype)

multiplies in and returns an array in the class specified by datatype.

sum(A)

• Sum of array elements; returns sums along different dimensions of an array. If A is floating yiibai, that is double or single, B is accumulated natively, that is in the same class as A, and B has the same class as A. If A is not floating yiibai, B is accumulated in double and B has class double.
• If A is a vector, sum(A) returns the sum of the elements.
• If A is a matrix, sum(A) treats the columns of A as vectors, returning a row vector of the sums of each column.
• If A is a multidimensional array, sum(A) treats the values along the first non-singleton dimension as vectors, returning an array of row vectors.

sum(A,dim)

Sums along the dimension of A specified by scalar dim.

sum(..., ‘double‘)

sum(..., dim,‘double‘)

Perform additions in double-precision and return an answer of type double, even if A has data type single or an integer data type. This is the default for integer data types.

sum(..., ‘native‘)

sum(..., dim,‘native‘)

Perform additions in the native data type of A and return an answer of the same data type. This is the default for single and double.

ceil(A)

Round toward positive infinity; rounds the elements of A to the nearest integers greater than or equal to A.

fix(A)

Round toward zero

floor(A)

Round toward negative infinity; rounds the elements of A to the nearest integers less than or equal to A.

idivide(a, b)

idivide(a, b,‘fix‘)

Integer division with rounding option; is the same as a./b except that fractional quotients are rounded toward zero to the nearest integers.

idivide(a, b, ‘round‘)

Fractional quotients are rounded to the nearest integers.

idivide(A, B, ‘floor‘)

Fractional quotients are rounded toward negative infinity to the nearest integers.

idivide(A, B, ‘ceil‘)

Fractional quotients are rounded toward infinity to the nearest integers.

mod (X,Y)

Modulus after division; returns X - n.*Y where n = floor(X./Y). If Y is not an integer and the quotient X./Y is within roundoff error of an integer, then n is that integer. The inputs X and Y must be real arrays of the same size, or real scalars (provided Y ~=0).

Please note:

• mod(X,0) is X
• mod(X,X) is 0
• mod(X,Y) for X~=Y and Y~=0 has the same sign as Y

rem (X,Y)

Remainder after division; returns X - n.*Y where n = fix(X./Y). If Y is not an integer and the quotient X./Y is within roundoff error of an integer, then n is that integer. The inputs X and Y must be real arrays of the same size, or real scalars(provided Y ~=0).

Please note that:

• rem(X,0) is NaN
• rem(X,X) for X~=0 is 0
• rem(X,Y) for X~=Y and Y~=0 has the same sign as X.

round(X)

Round to nearest integer; rounds the elements of X to the nearest integers. Positive elements with a fractional part of 0.5 round up to the nearest positive integer. Negative elements with a fractional part of -0.5 round down to the nearest negative integer.

函數

描述

eq(a, b)

Tests whether a is equal to b

ge(a, b)

Tests whether a is greater than or equal to b

gt(a, b)

Tests whether a is greater than b

le(a, b)

Tests whether a is less than or equal to b

lt(a, b)

Tests whether a is less than b

ne(a, b)

Tests whether a is not equal to b

isequal

Tests arrays for equality

isequaln

Tests arrays for equality, treating NaN values as equal

運算符

描述

<

Less than

<=

Less than or equal to

>

Greater than

>=

Greater than or equal to

==

Equal to

~=

Not equal to

函數

描述

and(A, B)

Finds logical AND of array or scalar inputs; performs a logical AND of all input arrays A, B, etc. and returns an array containing elements set to either logical 1 (true) or logical 0 (false). An element of the output array is set to 1 if all input arrays contain a nonzero element at that same array location. Otherwise, that element is set to 0.

not(A)

Finds logical NOT of array or scalar input; performs a logical NOT of input array A and returns an array containing elements set to either logical 1 (true) or logical 0 (false). An element of the output array is set to 1 if the input array contains a zero value element at that same array location. Otherwise, that element is set to 0.

or(A, B)

Finds logical OR of array or scalar inputs; performs a logical OR of all input arrays A, B, etc. and returns an array containing elements set to either logical 1 (true) or logical 0 (false). An element of the output array is set to 1 if any input arrays contain a nonzero element at that same array location. Otherwise, that element is set to 0.

xor(A, B)

Logical exclusive-OR; performs an exclusive OR operation on the corresponding elements of arrays A and B. The resulting element C(i,j,...) is logical true (1) if A(i,j,...) or B(i,j,...), but not both, is nonzero.

all(A)

Determine if all array elements of array A are nonzero or true.

• If A is a vector, all(A) returns logical 1 (true) if all the elements are nonzero and returns logical 0 (false) if one or more elements are zero.
• If A is a nonempty matrix, all(A) treats the columns of A as vectors, returning a row vector of logical 1‘s and 0‘s.
• If A is an empty 0-by-0 matrix, all(A) returns logical 1 (true).
• If A is a multidimensional array, all(A) acts along the first nonsingleton dimension and returns an array of logical values. The size of this dimension reduces to 1 while the sizes of all other dimensions remain the same.

all(A, dim)

Tests along the dimension of A specified by scalar dim.

any(A)

Determine if any array elements are nonzero; tests whether any of the elements along various dimensions of an array is a nonzero number or is logical 1 (true). The any function ignores entries that are NaN (Not a Number).

• If A is a vector, any(A) returns logical 1 (true) if any of the elements of A is a nonzero number or is logical 1 (true), and returns logical 0 (false) if all the elements are zero.
• If A is a nonempty matrix, any(A) treats the columns of A as vectors, returning a row vector of logical 1‘s and 0‘s.
• If A is an empty 0-by-0 matrix, any(A) returns logical 0 (false).
• If A is a multidimensional array, any(A) acts along the first nonsingleton dimension and returns an array of logical values. The size of this dimension reduces to 1 while the sizes of all other dimensions remain the same.

any(A,dim)

Tests along the dimension of A specified by scalar dim.

false

Logical 0 (false)

false(n)

is an n-by-n matrix of logical zeros

false(m, n)

is an m-by-n matrix of logical zeros.

false(m, n, p, ...)

is an m-by-n-by-p-by-... array of logical zeros.

false(size(A))

is an array of logical zeros that is the same size as array A.

false(...,‘like‘,p)

is an array of logical zeros of the same data type and sparsity as the logical array p.

ind = find(X)

Find indices and values of nonzero elements; locates all nonzero elements of array X, and returns the linear indices of those elements in a vector. If X is a row vector, then the returned vector is a row vector; otherwise, it returns a column vector. If X contains no nonzero elements or is an empty array, then an empty array is returned.

ind = find(X, k)

ind = find(X, k, ‘first‘)

Returns at most the first k indices corresponding to the nonzero entries of X. k must be a positive integer, but it can be of any numeric data type.

ind = find(X, k, ‘last‘)

returns at most the last k indices corresponding to the nonzero entries of X.

[row,col] = find(X, ...)

Returns the row and column indices of the nonzero entries in the matrix X. This syntax is especially useful when working with sparse matrices. If X is an N-dimensional array with N > 2, col contains linear indices for the columns.

[row,col,v] = find(X, ...)

Returns a column or row vector v of the nonzero entries in X, as well as row and column indices. If X is a logical expression, then v is a logical array. Output v contains the non-zero elements of the logical array obtained by evaluating the expression X.

islogical(A)

Determine if input is logical array; returns true if A is a logical array and false otherwise. It also returns true if A is an instance of a class that is derived from the logical class.

logical(A)

Convert numeric values to logical; returns an array that can be used for logical indexing or logical tests.

true

Logical 1 (true)

true(n)

is an n-by-n matrix of logical ones.

true(m, n)

is an m-by-n matrix of logical ones.

true(m, n, p, ...)

is an m-by-n-by-p-by-... array of logical ones.

true(size(A))

is an array of logical ones that is the same size as array A.

true(...,‘like‘, p)

is an array of logical ones of the same data type and sparsity as the logical array p.

p

q

p & q

p | q

p ^ q

0

0

0

0

0

0

1

0

1

1

1

1

1

1

0

1

0

0

1

1

函數

目的/作用

bitand(a, b)

Bit-wise AND of integers a and b

bitcmp(a)

Bit-wise complement of a

bitget(a,pos)

Get bit at specified position pos, in the integer array a

bitor(a, b)

Bit-wise OR of integers a and b

bitset(a, pos)

Set bit at specific location pos of a

bitshift(a, k)

Returns a shifted to the left by k bits, equivalent to multiplying by 2^k. Negative values of k correspond to shifting bits right or dividing by 2^|k| and rounding to the nearest integer towards negative infinite. Any overflow bits are truncated.

bitxor(a, b)

Bit-wise XOR of integers a and b

swapbytes

Swap byte ordering

函數

描述

intersect(A,B)

Set intersection of two arrays; returns the values common to both A and B. The values returned are in sorted order.

intersect(A,B,‘rows‘)

Treats each row of A and each row of B as single entities and returns the rows common to both A and B. The rows of the returned matrix are in sorted order.

ismember(A,B)

Returns an array the same size as A, containing 1 (true) where the elements of A are found in B. Elsewhere, it returns 0 (false).

ismember(A,B,‘rows‘)

Treats each row of A and each row of B as single entities and returns a vector containing 1 (true) where the rows of matrix A are also rows of B. Elsewhere, it returns 0 (false).

issorted(A)

Returns logical 1 (true) if the elements of A are in sorted order and logical 0 (false) otherwise. Input A can be a vector or an N-by-1 or 1-by-N cell array of strings. A is considered to be sorted if A and the output of sort(A) are equal.

issorted(A, ‘rows‘)

Returns logical 1 (true) if the rows of two-dimensional matrix A are in sorted order, and logical 0 (false) otherwise. Matrix A is considered to be sorted if A and the output of sortrows(A) are equal.

setdiff(A,B)

Set difference of two arrays; returns the values in A that are not in B. The values in the returned array are in sorted order.

setdiff(A,B,‘rows‘)

Treats each row of A and each row of B as single entities and returns the rows from A that are not in B. The rows of the returned matrix are in sorted order.

The ‘rows‘ option does not support cell arrays.

setxor

Set exclusive OR of two arrays

union

Set union of two arrays

unique

Unique values in array

函數

描述

intersect(A,B)

Set intersection of two arrays; returns the values common to both A and B. The values returned are in sorted order.

intersect(A,B,‘rows‘)

Treats each row of A and each row of B as single entities and returns the rows common to both A and B. The rows of the returned matrix are in sorted order.

ismember(A,B)

Returns an array the same size as A, containing 1 (true) where the elements of A are found in B. Elsewhere, it returns 0 (false).

ismember(A,B,‘rows‘)

Treats each row of A and each row of B as single entities and returns a vector containing 1 (true) where the rows of matrix A are also rows of B. Elsewhere, it returns 0 (false).

issorted(A)

Returns logical 1 (true) if the elements of A are in sorted order, and logical 0 (false) otherwise. Input A can be a vector or an N-by-1 or 1-by-N cell array of strings. A is considered to be sorted if A and the output of sort(A) are equal.

issorted(A, ‘rows‘)

Returns logical 1 (true) if the rows of two-dimensional matrix A are in sorted order, and logical 0 (false) otherwise. Matrix A is considered to be sorted if A and the output of sortrows(A) are equal.

setdiff(A,B)

Set difference of two arrays; returns the values in A that are not in B. The values in the returned array are in sorted order.

setdiff(A,B,‘rows‘)

Treats each row of A and each row of B as single entities and returns the rows from A that are not in B. The rows of the returned matrix are in sorted order.

The ‘rows‘ option does not support cell arrays.

setxor

Set exclusive OR of two arrays

union

Set union of two arrays

unique

Unique values in array

命令

作用/目的

disp

顯示一個數組或字符串的內容。

fscanf

閱讀從文件格式的數據。

format

控制屏幕顯示的格式。

fprintf

執行格式化寫入到屏幕或文件。

input

顯示提示並等待輸入。

;

禁止顯示網版印刷

格式代碼

目的/作用

%s

Format as a string.

%d

Format as an integer.

%f

Format as a floating yiibai value.

%e

Format as a floating yiibai value in scientific notation.

%g

Format in the most compact form: %f or %e.

Insert a new line in the output string.

Insert a tab in the output string.

Format函數

最多可顯示

format short

Four decimal digits (default).

format long

16 decimal digits.

format short e

Five digits plus exponent.

format long e

16 digits plus exponents.

format bank

Two decimal digits.

format +

Positive, negative, or zero.

format rat

Rational approximation.

format compact

Suppresses some line feeds.

format loose

Resets to less compact display mode.

命令

作用/目的

cat

Concatenates arrays.連接數組

find

Finds indices of nonzero elements.

length

Computes number of elements.

linspace

Creates regularly spaced vector.

logspace

Creates logarithmically spaced vector.

max

Returns largest element.

min

Returns smallest element.

prod

Product of each column.

reshape

Changes size.

size

Computes array size.

sort

Sorts each column.

sum

Sums each column.

eye

Creates an identity matrix. 創建單位矩陣

ones

Creates an array of ones. 創建一個1的數組

zeros

Creates an array of zeros. 創建一個0數組

cross

Computes matrix cross products.計算矩陣交叉積

dot

Computes matrix dot products. 點積

det

Computes determinant of an array.計算行列式

inv

Computes inverse of a matrix.計算行列式的逆

pinv

Computes pseudoinverse of a matrix.計算行列式的違逆

rank

Computes rank of a matrix.計算行列式的秩

rref

Computes reduced row echelon form.

cell

Creates cell array.

celldisp

Displays cell array.

cellplot

Displays graphical representation of cell array.

num2cell

Converts numeric array to cell array.

deal

Matches input and output lists.

iscell

Identifies cell array.

命令

作用/目的

axis

Sets axis limits.

fplot

Intelligent plotting of functions.

grid

Displays gridlines.

plot

Generates xy plot.

print

Prints plot or saves plot to a file.

title

Puts text at top of plot.

xlabel

Adds text label to x-axis.

ylabel

Adds text label to y-axis.

axes

Creates axes objects.

close

Closes the current plot.

close all

Closes all plots.

figure

Opens a new figure window.

gtext

Enables label placement by mouse.

hold

Freezes current plot.

legend

Legend placement by mouse.

refresh

Redraws current figure window.

set

Specifies properties of objects such as axes.

subplot

Creates plots in subwindows.

text

Places string in figure.

bar

Creates bar chart.

loglog

Creates log-log plot.

polar

Creates polar plot.

semilogx

Creates semilog plot. (logarithmic abscissa).

semilogy

Creates semilog plot. (logarithmic ordinate).

stairs

Creates stairs plot.

stem

Creates stem plot.