Creating Matrix from List in Mathematica

In summary, the conversation was about someone struggling to create a matrix from a list of numbers. They shared the code they were using and asked for help. Another person provided a solution using the Partition function and the original person expressed their gratitude for the quick response.
  • #1
tau1777
30
0
Hi All,

So I've been trying to create a matrix from a list of numbers and have been unsuccessful so far. Basically I would like to change

list = {1,2,3,4,5,6,7,8,9}

into

matrix =
1 2 3
4 5 6
7 8 9

The real problem is just a much bigger matrix, but if anyone can tell me how to do this I can do the bigger problem.

Thanks so much to anyone who helps.
 
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  • #2
In[1]:= list={1,2,3,4,5,6,7,8,9};matrix=Partition[list,3]
Out[2]= {{1,2,3},{4,5,6},{7,8,9}}
 
  • #3
Thank you so much Bill. This works like charm. Can't believe I spent a day scouring other forums for this. Thanks for the very quick response time...this was starting to drive me crazy because I was convinced it was a command that I just didn't know and it was.

Thanks. Thanks. Thanks.
 

1. How can I create a matrix from a list in Mathematica?

To create a matrix from a list in Mathematica, you can use the function "ArrayReshape". This function takes in the list as its first argument and the dimensions of the desired matrix as its second argument. For example, if you have a list of length 9 and want to create a 3x3 matrix, you would use the command "ArrayReshape[list, {3,3}]."

2. Can I create a matrix with specific values using a list in Mathematica?

Yes, you can use the function "ArrayFlatten" to create a matrix with specific values from a list in Mathematica. This function takes in a nested list as its argument, where each sublist represents a row in the matrix. For example, if you have a list of lists with values {{1,2},{3,4}} and want to create a 2x2 matrix with these values, you would use the command "ArrayFlatten[{{1,2},{3,4}}]."

3. Is it possible to create a matrix with unequal row lengths from a list in Mathematica?

Yes, you can use the function "SparseArray" to create a matrix with unequal row lengths from a list in Mathematica. This function takes in a list of rules, where the keys represent the positions in the matrix and the values represent the corresponding elements. For example, if you have a list with values {1,2,3,4,5} and want to create a matrix with two rows of lengths 3 and 2 respectively, you would use the command "SparseArray[{1 -> {1, 2, 3}, 2 -> {4, 5}}]."

4. How can I convert a matrix into a list in Mathematica?

To convert a matrix into a list in Mathematica, you can use the function "Flatten". This function takes in the matrix as its argument and returns a flattened list of all the elements. You can also specify the level of flattening using the optional argument "n". For example, to convert a 2x2 matrix into a list of length 4, you would use the command "Flatten[matrix, 1]."

5. Can I create a matrix with random values from a list in Mathematica?

Yes, you can use the function "RandomArray" to create a matrix with random values from a list in Mathematica. This function takes in the list as its first argument and the dimensions of the desired matrix as its second argument. Additionally, you can specify the range of random values using the optional arguments "Min" and "Max". For example, to create a 3x3 matrix with random values between 1 and 10, you would use the command "RandomArray[list, {3,3}, Min -> 1, Max -> 10]."

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