【正文】 0 0 0 0 0 0 0 0 0 111 A(:,6)=222 A = 1 4 7 0 0 222 2 5 8 0 0 222 3 6 9 0 0 222 0 0 0 0 0 222 0 0 0 0 111 222 （2）多次尋訪擴展法AA=A(:,[1:6,1:6]) AA = 1 4 7 0 0 222 1 4 7 0 0 222 2 5 8 0 0 222 2 5 8 0 0 222 3 6 9 0 0 222 3 6 9 0 0 222 0 0 0 0 0 222 0 0 0 0 0 222 0 0 0 0 111 222 0 0 0 0 111 222 （3）合成擴展法B=ones(2,6) B = 1 1 1 1 1 1 1 1 1 1 1 1 AB_r=[A。A(2,2,2)=1 A(:,:,1) =0 00 0A(:,:,2) =0 0 0 1 B(2,5,:)=1:3 B(:,:,1) = 0 0 0 0 0 0 0 0 0 1B(:,:,2) = 0 0 0 0 0 0 0 0 0 2B(:,:,3) = 0 0 0 0 0 0 0 0 0 3 【】低維數(shù)組合成高維數(shù)組。（1）a=0/0,b=0*log(0),c=infinf Warning: Divide by zero.a = NaNWarning: Log of zero.b = NaNc = NaN （2）0*a,sin(a) ans = NaNans = NaN （3）a==nan ans = 0 （4）a~=nana==bbc ans = 1ans = 0ans = 0 （5）class(a)isnan(a) ans =doubleans = 1 【】非數(shù)元素的尋訪rand(39。subplot(1,2,1),plot(t,y),axis([7,7,]),xlabel(39。A1 L1 = 1 1 1 1 0 0 0L2 = 0 0 0 1 0 0 0L3 = 0 0 0 1 0 0 0L4 = 0 0 1 1 0 0 0 【】邏輯操作應(yīng)用之一：逐段解析函數(shù)的計算和表現(xiàn)。),axis([0 10 1 1])subplot(1,3,3),plot(t,z2,39。逐段解析函數(shù)39。t39。),ylabel(39。) Warning: Divide by zero. 極限處理前后的圖形對照 邏輯操作【】邏輯操作示例。t=2*pi:pi/10:2*pi。permute(A,[2,3,1]) ans(:,:,1) = 1 7 13 3 9 15 5 11 17ans(:,:,2) = 2 8 14 4 10 16 6 12 18 permute(A,[1,3,2]) ans(:,:,1) = 1 7 13 2 8 14ans(:,:,2) = 3 9 15 4 10 16ans(:,:,3) = 5 11 17 6 12 18 【】“孤維”的撤消和降維。 s = 2 5 6 8 10 11 17 18 R(s)=111 R = [ii,jj]=find(R==111)。a=4:4A=reshape(a,3,3) a = Columns 1 through 8 4 3 2 1 0 1 2 3 Column 9 4A = 4 1 2 3 0 3 2 1 4 a1=diag(A,1) a1 = 1 3 A1=diag(a1,1) A1 = 0 0 0 1 0 0 0 3 0 【】數(shù)組轉(zhuǎn)置、對稱交換和旋轉(zhuǎn)操作后果的對照比較。余多項式為 39。A=[11 12 13。A=zeros(2,5)。) x = Columns 1 through 7 0 Columns 8 through 11 y = Columns 1 through 7 0 Columns 8 through 11 一維數(shù)組的創(chuàng)建和尋訪 一維數(shù)組的創(chuàng)建 一維數(shù)組的子數(shù)組尋訪和賦值【】子數(shù)組的尋訪（Address）。 本章系統(tǒng)闡述：一、二維數(shù)值數(shù)組的創(chuàng)建、尋訪；數(shù)組運算和矩陣運算的區(qū)別；實現(xiàn)數(shù)組運算的基本函數(shù)；多項式的表達(dá)、創(chuàng)建和操作；常用標(biāo)準(zhǔn)數(shù)組生成函數(shù)和數(shù)組構(gòu)作技法；高維數(shù)組的創(chuàng)建、尋訪和操作；非數(shù)NaN、“空”數(shù)組概念和應(yīng)用；關(guān)系和邏輯操作。a=。N_L=Num==L c_N=class(Num) c_L=class(L) N_L = 1 1 1 1 1 1 1 1 1 1c_N =doublec_L =double （2）islogical(Num) Y=A(Num) ans = 0??? Index into matrix is negative or zero. See release notes on ch