FAQ Database Discussion Community

## How to get indices from a list/ndarray?

python,numpy,matrix,indices
I have a list which looks like: [[0,1,2], [1,2,3], [2,3,4], [3,4,5]] I can make it to an array like: array([[0,1,2], [1,2,3], [2,3,4], [3,4,5]]) So all together I have 4 rows and each row has 3 columns. Now I want to find the indices of all the elements which are greater...

## R: column and row indices with largest values

r,matrix,indices
Suppose we have a matrix that looks as follows: -0.3 0.2 0.001 -0.4 0.5 0.25 0.45 0.2 -0.001 0.02 0.8 - 0.2 0.35 0.1 0.1 0.25 -0.14 -0.1 0.02 0.4 Now I want to find that part of the matrix which has dimension 2 x 2 AND has the largest...

## Is there a way to generate a list of indices using numpy

python,numpy,dynamically-generated,indices
Can I use numpy to generate repeating patterns of indices for example. 0, 1, 2, 3, 4, 5, 0, 6, 7, 8, 9, 10, 0, 11, 12, 13, 14, 15 or 0,1,2,1,2,3,4,5,6,5,6,7 Is there a method in numpy i can use to generate these lists between a range ? currently...

## Error with square root function and powers in Matlab R2014b [SOLVED] [closed]

matlab,indices,square-root
I am carrying out a series of calculations using the sqrt() function. My colleagues and I have noticed that we get different results when using the same inputs. Has anyone encountered this problem before? This is an example: input1 = 4; input2 = 8; result = sqrt(input1^2 + input2^2) Result...

## Histograms: “TypeError, list indices must be integers, not str”

python,list,histogram,typeerror,indices
I am trying to make a function that will take a character and a histogram and add an instance of that character to the histogram. My code so far is like this: def add_to_hist(character, histogram): """Takes a character and a histogram and adds an occurrence of that character to the...

## Python: TypeError: list indices must be integers, not list

python,list,loops,indices
I've got two lists of coordinates, they look like this: list_kp2_ok: [[1185.60009765625, 933.6000366210938], [1310.4000244140625, 828.0000610351562], [1067.0, 979.0], [1310.0, 828.0], [1423.2000732421875, 814.800048828125], [1306.0, 828.0], [3634.0, 605.0], [1308.0960693359375, 827.7120971679688], [1422.7200927734375, 815.0400390625], [1185.1199951171875, 933.1200561523438], [1186.56005859375, 923.0400390625], [1306.3681640625, 829.4401245117188], [1194.393798828125, 839.80810546875], [1187.1361083984375, 922.7520751953125],...

## R: Select multiple values from vector of sequences

r,vector,sequence,indices
In R I'm trying to figure out how to select multiple values from a predefined vector of sequences (e.g. indices = c(1:3, 4:6, 10:12, ...)). In other words, if I want a new vector with the 3rd, 5th, and 7th entries in "indices", what syntax should I use to get...

## find row indices of different values in matrix

matlab,find,row,cell,indices
Having matrix A (n*2) as the source and B as a vector containing a subset of elements A, I'd like to find the row index of items. A=[1 2;1 3; 4 5]; B=[1 5]; F=arrayfun(@(x)(find(B(x)==A)),1:numel(B),'UniformOutput',false) gives the following outputs in a cell according to this help page [2x1 double] [6]...

## find indices x,y of a matrix of specific values in python

python,matrix,multidimensional-array,indices
I convert a list of integers to a two dimensinal array like this: data = numpy.array( l ) shape = ( 10, 30 ) data = data.reshape( shape ) I try to get the indices x,y of the matrix of the values that are bigger than some threshold and lower...

## In C# is it possible to have an custom Indexer property of a type that is NOT a string or an int?

c#,properties,unity3d,indices,indexer
In C# is it possible to have an Indexer property of a type that is not a string or an int? For example I have a custom object that is a map of 2D vector coordinates. Taking the basics of my map class to be... public class TileMap { ///...

## I'm trying to make the “merge function” work by writing a Callback.

I think my understanding of callbacks is pretty green. But this is what have so far and my function is only adding the first index in each array together. var merge = function(array1, array2, callback){ for (var i = 0; i < array1.length; i++) { return array1[i] + array2[i]; };...

## Trouble with for loops in Python 3: getting the index in string2 of an element from string1

python,python-3.x,encryption,indices,vigenere
I am trying to write a program that will take a file and encode it using the Viginère cipher. I've run into a little bump with indices. I've defined my strings text and alphabet like this: import string alphabet = string.ascii_lowercase ciphertext = open("black_hole.txt","r") ciphertext = ciphertext.read() text = ""...

## Swapping indices with values in a Python list?

python,list,python-3.x,swap,indices
(No, this is not a homework assignment nor a contest, even though it might look like one.) I have a list A in Python that contains the numbers range(0, len(A)). The numbers are not in order, but all of them exist in the list. I'm looking for a simple way...

## How to read in FBX 2014 indices properly for DirectX?

c++,directx,mesh,indices,fbx
I've been having this very annoying problem for the past weekend. I have to be able to to read in a triangulated 2014 FBX file that contains a mesh exported from Maya and read in it's vertices and indices to be passed to the renderer (DirectX) for the DrawIndexed call....

## How do I use matlab ismember in data structures with multiple nested fields?

arrays,string,matlab,data-structures,indices
In matlab I have the following 2 data structures b and c defined as follows. b(1).b = struct('c',{'a', 'b', 'c'}) c(1).b = struct('c',{'b', 'a', 'c'}) Now I want to use ismember to find out if the elements of b(1).b.c are contained in c(1).b.c and if so, which indices of c(1).b.c...

## Is there an easy way to group columns in a Pandas DataFrame?

pandas,dataframes,indices,columnname
I am trying to use Pandas to represent motion-capture data, which has T measurements of the (x, y, z) locations of each of N markers. For example, with T=3 and N=4, the raw CSV data looks like: T,Ax,Ay,Az,Bx,By,Bz,Cx,Cy,Cz,Dx,Dy,Dz 0,1,2,1,3,2,1,4,2,1,5,2,1 1,8,2,3,3,2,9,9,1,3,4,9,1 2,4,5,7,7,7,1,8,3,6,9,2,3 This is really simple to load into a DataFrame,...

## Indices trick used for several components

Consider this fully working code: #include <type_traits> template <typename T, typename IndexPack> struct Make; template <typename T, template <T...> class P, T... Indices> struct Make<T, P<Indices...>> { using type = P<(Indices+1)..., (-3*Indices)..., (Indices-1)...>; }; template <int...> class Pack; int main() { static_assert (std::is_same<Make<int, Pack<1,2,3,4>>::type, Pack<2,3,4,5, -3,-6,-9,-12, 0,1,2,3>>::value, "false"); } What...

## Multiple indices under a single name in kibana is possible?

indexing,customization,kibana,indices
I want multiple indices to be under one name.. How can i do that in kibana... as shown in this picture..so that the logs ( app,server,db) of the server1 and the logs of server 2 under it. How can we customize to make multiple indices under one name. { http://i.stack.imgur.com/t3eV8.png...

## Indexing a numpy array with a list of tuples

numpy,multidimensional-array,indices
Why can't I index an ndarray using a list of tuple indices like so? idx = [(x1, y1), ... (xn, yn)] X[idx] Instead I have to do something unwieldy like idx2 = numpy.array(idx) X[idx2[:, 0], idx2[:, 1]] # or more generally: X[tuple(numpy.vsplit(idx2.T, 1)[0])] Is there a simpler, more pythonic way?...

## Find column locations of vector elements inside a matrix

matlab,matrix,indices
Given a vector such as a = [2 5 9] and a matrix such as 8 11 5 b = 2 6 1 4 9 3 What's the best way to find which column of b contains each element of a? In this example I'd want an output like [1...