How to write a range of numbers in MATLAB?

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Abdul Rahim Mahayadin
评论： Walter Roberson 2021-7-27
Hi, I am trying to generate a speed range in MATLAB. Let V is the speed, then how to write the coding to find the speed range of:
0<V<=12
12<V<=20
20<V<=30
30<V<=40
40<V<=50
50<V<=60
60<V<=70
70<V<=80
80<V<=90
90<V<=100
100<V<=110
V>110

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回答（4 个）

Walter Roberson
Walter Roberson 2018-4-9
https://www.mathworks.com/help/comm/ug/quantization.html
or you can use the second output of histc() or the third output of histcounts()
njj1
njj1 2018-4-18 
ranges = [0,12,20:10:110]; %end points of requested speeds
for i = 1:numel(ranges)-1
   v{i} = V((V>ranges(i) & (V<=ranges(i+1))); %speeds between endpoints
   numV{i} = numel(v{i}); %number of speed entries between endpoints
end
v{end+1} = V(V>110);
Walter Roberson
Walter Roberson 2021-7-22
编辑：Walter Roberson 2021-7-22
Ran in:
theta = (0:60).';
and remember to use cosd() and sind()
Notice the .' there: it is transposing the 0:60 from a row vector into a column vector. When you combine this with row vectors, then the result would be to implicitly expand to two dimensions. For example,
v = 1:100;
theta = (0:60).';
dist = (v - v.^2/100) .* sind(theta);
surf(v, theta, dist, 'edgecolor', 'none')
size(v), size(theta), size(dist)
ans = 1×2
1 100
ans = 1×2
61 1
ans = 1×2
61 100
  2 个评论
rahim njie
rahim njie 2021-7-26
thanks but this didnt work for what im trying to do. i would like to calculate something at every angle between 0-60 degrees. this is my code so far if it helps:
theta= (1:60).'; % precession angle
w_s = 10; % angular velocity of spin
a_s = 6; % angualar acceleration of spin
w_n = 3; % angular velocity of nutation
a_n = 2; % augalar acceleration of nutation
w_p = 5; % angular velocity of precession
a_p = 4; % angular acceleration of precession
%% Geometry values
rA = [0 7.4103 7.1651];
%% vectors
vw_s = [0 w_s*sind(theta) w_s*cosd(theta)]; % spin vector
vw_p = [0 0 w_p]; % precession vector
vw_n = [-w_n 0 0]; % nutation vector
%% Angualar velocity
wi = [-w_n 0 0]; % i component of W
wj = [0 w_s*sind(theta) 0]; % j component W
wk = [ 0 0 (w_p + w_s*cosd(theta))]; % k component of W
W = wi + wj + wk; % Angular Velocity;
Walter Roberson
Walter Roberson 2021-7-27
Ran in:
theta= (1:60).'; % precession angle
w_s = 10; % angular velocity of spin
a_s = 6; % angualar acceleration of spin
w_n = 3; % angular velocity of nutation
a_n = 2; % augalar acceleration of nutation
w_p = 5; % angular velocity of precession
a_p = 4; % angular acceleration of precession
%% Geometry values
rA = [0 7.4103 7.1651];
%% vectors
Z = zeros(size(theta));
vw_s = [Z, w_s*sind(theta), w_s*cosd(theta)]; % spin vector
vw_p = [0 0 w_p]; % precession vector
vw_n = [-w_n 0 0]; % nutation vector
%% Angualar velocity
wi = [-w_n 0 0]; % i component of W
wj = [Z w_s*sind(theta) Z]; % j component W
wk = [ Z Z (w_p + w_s*cosd(theta))]; % k component of W
W = wi + wj + wk; % Angular Velocity;
size(W)
ans = 1×2
60 3

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KSSV
KSSV 2018-4-9
V = 1:100 ;
idx = V>=10 & V<=20 ; % Get indices of velocities lying between 10 to 20
V(idx)
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KSSV
KSSV 2021-7-22
Ran in:
Yes...you can test it yourself.
v = 1:100
v = 1×100
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
rahim njie
rahim njie 2021-7-22
thank.
Also i have written code that solves 3D kinematics problem. the code calculates angular velocity at set precsion angle of 60. what function do i use that will allow me to use the same code but calculate the velocity and angle from 1-60 degrees.
i have vectors in some of the calucations so using 'theta= 1:60' Caused erros
thanks

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