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POAppending a list of lists in python
 

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  1. POAppending a list of lists in python
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    <p>I have a list of lists. I want to add the elements of an array to one of the sublists, but the one I add it to depends on the length of the array.</p> <pre><code>import numpy as np import numpy.linalg from numpy import matrix from scipy.linalg import inv,det,eig import random import matplotlib.pyplot as plt import pylab from numpy import vstack from scipy.optimize import curve_fit from array import array import copy def getstabmat(orign, small, specsize, alln): #FIRST MAKE THE MATRIX matfound=0 while (matfound==0): n=orign A=np.empty((n,n)) I=np.ones((n)) for i in range(0,n): for j in range(i+1,n): A[j,i]=random.random() for i in range(0,n): for j in range(i+1,n): A[i,j] = A[j,i] for i in range(n): A[i,i]=1 #NOW REMOVE NEGATIVE ELEMENTS AND KEEP SOLVING allpos=0 while (allpos !=1): #loop for dealing just with getting it positive x = numpy.linalg.solve(A,I) if any(tl&lt;small for tl in x): #if any of the solutions in x are negative or small p=np.where(x==min(x)) # find the most negative solution, p is the position x=np.delete(x, p, 0) A=np.delete(A, p, 0) A=np.delete(A, p, 1) I=np.delete(I, p, 0) n=n-1 else: allpos=1 #now test for stability, only do it once and remove one element before returning to check positiveness. J=np.empty((n,n)) # make empty jacobian for i in range (0,n): for j in range (0,n): if (i==j): # if we are looking at the diagonal of the matrix, there is a special formula for species dealing with itself tsum = 0 for k in range (0,n): #for the summation part tsum = tsum + A[i][k]*x[k] # x is vector of fixed points obtained before J[i][j] = 1 - A[i][j]*x[i] - tsum else: J[i][j] = -A[i][j]*x[i] #now jacobian at fixed point has been constructed Jeig, Jvec = eig(J) # get the eigenvalues and eigenvectors #run through eigenvalues and find out if any of them are positive if any(tl&gt;0 for tl in Jeig.real): #if any eigenvalues are positive matfound=0 else: if ((alln==0 and len(A)==specsize) or alln==1): # if the matrix found has five species matfound=1 else: matfound=0 return A, x def main(): mats=3 #number of matrices to find orign=15 alln=1 #if alln=1, that means that all sizes of stable matrix should be returned n=5 # the number of different species wanted in each matrix small=0.0001 #the fractional size that a species is when it is considered to be extinct a=0 sortedspec=[[]]*10 specad=[] while (a&lt;mats): #while all the mats have not been found print a A, specfp = getstabmat(orign, small, n, alln) #15 is the original size of matrix to pass to fnc.n is the size that will be returned a=a+1 print specfp print len(specfp) for i in range (0,len(specfp)): (sortedspec[len(specfp)]).append(specfp[i]) print sortedspec if __name__ == '__main__': main() </code></pre> <p>So if:</p> <pre><code>specfp = [ 0.78076862 0.79608003 0.50719552] </code></pre> <p>Then I want each element to be added to the list sortedspec[3]. However, I end up with each element of my array being added to EVERY list element. Why is it doing this and can I fix it? Thankyou.</p>
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    1. USCatherine Georgia
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    1. This table or related slice is empty.
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    1. This table or related slice is empty.
    1. COMaybe start by removing everything from your code that is not related to this problem.
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    2. COWhy not use defaultdict and append elements (or add lists)?
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      1. POAppending a list of lists in python
      1. USAndy Hayden
    3. COpossible duplicate of [Python list confusion](http://stackoverflow.com/questions/5957341/python-list-confusion)
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      1. POAppending a list of lists in python
      1. USMartijn Pieters
 

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