how to fill a matrix with different size vectors

I have a for cycle. each time the output is of different lenght.

I would like to put each output in the rows of a unique matrix and in the same time to save the vectors with consecutive names, like output1, output2, outpu3....

for i=1:4:size(index,2) 
    step=degree(index(i):index(i+3))'
end

[madhan ravi]

Don't name a variable step and degree because there are inbuilt MATLAB functions.

help step

 STEP  Step response of dynamic systems.
 
    [Y,T] = STEP(SYS) computes the step response Y of the dynamic system SYS. 
    The time vector T is expressed in the time units of SYS and the time 
    step and final time are chosen automatically. For multi-input systems,
    independent step commands are applied to each input channel. If SYS has 
    NY outputs and NU inputs, Y is an array of size [LENGTH(T) NY NU] where 
    Y(:,:,j) contains the step response of the j-th input channel.
 
    For state-space models, 
       [Y,T,X] = STEP(SYS) 
    also returns the state trajectory X, an array of size [LENGTH(T) NX NU] 
    for a system with NX states and NU inputs.
 
    For identified models (see IDMODEL),
       [Y,T,X,YSD] = STEP(SYS) 
    also computes the standard deviation YSD of the response Y (YSD is empty 
    if SYS does not contain parameter covariance information).
 
    [Y,...] = STEP(SYS,TFINAL) simulates the step response from t=0 to the 
    final time t=TFINAL (expressed in the time units of SYS). For discrete-
    time models with unspecified sample time, TFINAL is interpreted as  
    the number of sampling periods.
 
    [Y,...] = STEP(SYS,T) specifies the time vector T for simulation (in 
    the time units of SYS). For discrete-time models, T should be of the  
    form 0:Ts:Tf where Ts is the sample time. For continuous-time models, 
    T should be of the form 0:dt:Tf where dt is the sampling period for the 
    discrete approximation of SYS. 
 
    [Y,...] = STEP(SYS,...,OPTIONS) specifies additional options such as the
    step amplitude or input offset. Use stepDataOptions to create the option
    set OPTIONS.
 
    When called without output arguments, STEP(SYS,...) plots the step 
    response of SYS and is equivalent to STEPPLOT(SYS,...). See STEPPLOT 
    for additional graphical options for step response plots.
 
    See also STEPPLOT, stepDataOptions, IMPULSE, INITIAL, LSIM, LTIVIEW, 
    DYNAMICSYSTEM, IDLTI.

    Documentation for step
       doc control/step

    Other functions named step

       DynamicSystem/step    iddata/step    system/step

help degree

--- help for graph/degree ---

 DEGREE Degree of nodes in a graph
 
    D = DEGREE(G) returns the degree of each node of G, in a column vector.
 
    D = DEGREE(G, NODEIDS) returns the degree of the nodes specified by
    NODEIDS. NODEIDS can be a numeric array of node IDs or an array of
    node names. D has the same dimensions as NODEIDS.
 
    Example:
        % Create a graph, and then compute the degree of its nodes.
        s = [1 1 1 4 4 6 6 6];
        t = [2 3 4 5 6 7 8 9];
        G = graph(s,t);
        d = degree(G)
 
    Example:
        % Create a graph, and then compute the degree of a subset of nodes.
        s = {'a' 'a' 'a' 'd' 'd' 'f' 'f' 'f'};
        t = {'b' 'c' 'd' 'e' 'f' 'g' 'h' 'i'};
        G = graph(s,t)
        nodeIDs = {'a' 'c' 'e'}';
        d = degree(G,nodeIDs)
 
    See also GRAPH, NEIGHBORS, DIGRAPH/INDEGREE, DIGRAPH/OUTDEGREE

    Documentation for graph/degree
       doc graph.degree

    Other functions named degree

       laurpoly/degree

Answer 1

[KSSV]

Read about Cells. You can save them into cell.

N = 10 ; 
iwant = cell(N,1) ; 
for i = 1:N
    iwant{i} = rand(randperm(10,1),1) ; 
end

[matteo bottoni]

Honestly I am not understanding. Can you help me a little bit more? How can i mix cell with my cycle?

[KSSV]

step = cell([],1) ; 
count = 0; 
for i=1:4:size(index,2) 
    count = count+1 ; 
    step{count}=degree(index(i):index(i+3))'
end
step