python networkx: do networkx's centrality algorithms use a weighted adjacency matrix? 
Both of those algorithms as implemented in NetworkX will use edge weights
if specified with the edge attribute 'weight' (for each edge). If you do
not specify a weight on the edge the numeric value 1 will be used.
This is very unclear from the documentation. I've opened an issue at
https://github.com/networkx/networkx/issues/920
so the developers fix this.

Creating adjacency matrix 
based on the comments, suitable formats are either a threedimensional
array or a list of data.frames / data.tables.
library(data.table)
DT < data.table
### create a template matrix
# find all unique ID's and unique Club's
ids < unique(DT$id)
clubs < unique(DT$club)
# matrix template based on the number of ids & clubs
mat.template < matrix(0L, nrow=length(ids), ncol=length(clubs),
dimnames=list(ids, clubs))
# iterate over the unique values of year
DT < data.table(dat, key="id,club")
res < lapply(unique(DT$year), function(y) {
# index the matrix by the DT where y == year. Set those values to 1
mat < copy(mat.template)
mat[as.matrix(DT[y==year, list(id, club)])] < 1
mat
})
setattr(res, "names", unique(DT$year))
R

How to pad adjacency matrix cells in D3.js style? 
One possible solution is to use the pcolor method of pyplot, as it accepts
a kwarg edgecolor.
import matplotlib.pyplot as plt
import numpy as np
x = np.arange(6)
y = np.arange(6)
X, Y = np.meshgrid(x, y)
Z = np.random.rand(5, 5)
ax = plt.subplot(111, aspect='equal') # To make the cells square
ax.pcolor(X, Y, Z,
edgecolor='white', # Color of "padding" between cells
linewidth=2) # Width of "padding" between cells
plt.show()

karray tree to produce adjacency matrix 
I have an implementation of a kary tree (it is very similar to my nary
tree implementation that you linked to). It is not complete, but it should
give you enough to start on.
To generate an adjacency matrix, you would need a twodimensional array
with dimensions n x k. You would then have to traverse the tree and
populate the adjacency matrix. A row i would correspond to node i and
matrix[i][0] to matrix[i][k  1] would contain references to the k children
of node i. Of course, the order of the nodes in the adjacency matrix would
depend on your method of traversal.

Adjacency Matrix not populating correctly python 
The lists are all shallow copies of each other, so when you edit one you're
actually editing each row. Try this for initializing the matrix:
adj_matrix = [[0] * size for i in range(size)]

BFS graph traversal  Append new node to adjacency matrix 
By blanking the adjacency matrix and replacing it with a new one with the
updated size, all cells except (from, to) and (to, from) will be zero. You
need to make a new adjacency matrix with the new size, copy the data from
the old one, and only then overwrite the old one.

(OpenCV) Fast adjacency matrix computation from watershed 
The following is simple but very fast:
Mat getAdjacencyMatrix(const int* klabels, int width, int height, int K)
/////* Input:
////  int* klabels: the labeled watershed image (the intensity of
the watershed lines is 1)
////  int K: the number of superpixels (= kmax + 1)
//// * Output:
////  Mat M: the adjacency matrix (M[i][j] = M[i][j] = 1 if the
superpixels i and j are adjacent, and = 0 otherwise)
////*/
{
/// Create a KxK matrix and initialize to 0
Mat M(K, K, CV_32S, Scalar(0));
/// Scan the labeled image
for(int y=1; y < height1; y++)
{
for(int x=1; x < width1; x++)
{
// Get the label of the current pixel and the ones of its
neighbors
int k = klabels[y*width + x];
int kleft = kla

Find all the missing directed edges in an adjacency matrix 
An adjacency matrix like this should be symmetric. What about taking the
lower triangular portion, transposing it and comparing it to the upper
triangular portion? Something like this:
low = tril(m).transpose()
upp = triu(m)
missing = mod(low + upp, 2)
missing should be 1 where there are missing locations in the upper
triangular portion.
If all you care about it making sure the upper portion is right, you could
just do something like:
m = tril(m).transpose() + tril(m)

Given an nxn Adjacency matrix, how can one compute the number of triangles in the graph (Matlab)? 
The (i, j) element in the n'th power of an adjacency matrix A counts the
number of paths of length n starting at i and ending at j.
A triangle is a path of length 3 that starts and ends at the same node.
Therefore the i'th diagonal element of the 3rd power of A counts the number
of triangles that contain i as one of the nodes.
Each distinct triangle will be counted twice for each of the three nodes in
the graph (once in each direction, clockwise and anticlockwise).
Therefore the number of distinct triangles is trace(A^3) / 6.

Generate Weighted Random Boolean Matrix in Matlab 
I've wrote a very clear and simple code to understand:
mat5x5 = rand(5);
chanse_of_1s=.90% probability for 1s, just change it.
chanse_of_0s=.10% probability for 0s, just change it.
mat5x5 = arrayfun(@(x)sum(x >= cumsum([0, chanse_of_0s, chanse_of_1s])),
mat5x5)1
just chage the chanses!

create an adjacency list type structure from a list of pairs 
You can do this with LINQ's GroupBy method, like this:
var adj = sList
.GroupBy(p => p.val1)
.ToDictionary(g => g.Key, g => g.Select(p =>
p.val2).ToList());
Note that this would not compute a transitive closure of your graph, i.e.
only the direct links will be present.
In .NET 4 and up you can also use Tuple<int,int> instead of making
your own Pair class.

Graphs using Adjacency List in c++ 
Couple of things.
Because you are using malloc no constructor is ever called, and as
such the non primitive member adj is never constructed and is
NULL.
You are leaking memory since you never free/delete any of your dynamically
allocated memory.
If you are using C++ why are you using malloc instead of new and delete?
You don't have to say struct vertex in the sizeof for C++.
To fix it you could do:
vPtr node = new struct vertex(); // also change to delete instead of free
or
// use current malloc line, change adj to be a pointer to a list and new it
// but this will cause additional problems for you since you really need to
use a constructor for STL::list
node>adj = new list<int>;
Bottom line you really shouldn't be using malloc here.

inserting a new entry into adjacency list 
Why can't you do it in a simple way?
dict1[x3] = [y2, y4]
for yi in dict1[x3]:
if yi in dict2.keys():
dict2[yi].append(x3)
else:
dict2[yi] = [x3]

sql adjacency list children for node 
Try with CTE(About CTE):
DECLARE @SelectedNode INT = 103;
;WITH nodes AS
(
SELECT Node
, ParentNode
, GroupID
, Depth
FROM TableNodes WHERE Node = @SelectedNode
UNION ALL
SELECT tn.Node
, tn.ParentNode
, tn.GroupID
, tn.Depth FROM TableNode tn
INNER JOIN nodes n ON n.Node = tn.ParentNode
)
SELECT * FROM nodes;

Adjacency list representation of graphs 
I guess that the author of the article would call that structure an
incidence list, since nodes link to other nodes via edges rather than
directly. The incidence list/adjacency list distinction is nonstandard and
IMHO not terribly useful because both structures have similar performance
characteristics and because it's not clear that the distinction is
wellfounded if one strips away the list ADT.

adjacencylist representation of a directed graph 
Both are O(m + n) where m is the number of edges and n is the number of
vertices.
Start a set of counters, one for each vertex, one for indegree and out for
outdegree.
Scan the edges. For the out vertex of each edge, add one to the outdegree
counter for that vertex. For the in vertex of each edge, add one to the
indegree counter for that vertex. This is O(m) operation.
Output the outdegree and indegree counters for each vertex, which is
O(n).
That's how you get O(m + n).

Mysql Adjacency List Model, My query result is not what I want 
Mike has no children so just add such persons with UNION to your query.
Also you should use INNER JOIN instead of LEFT JOIN
select * from
(
SELECT
t1.name as level1, t2.name as level2
FROM
People as t1
JOIN
People as t2 ON t2.parent_id = t1.id
UNION
select t1.Name as level1, '' as level2
from People t1
where Parent_id=0
and not exists(select 1 from People where Parent_id=t1.Id)
) People
ORDER BY
level1, level2
SQLFiddle demo

Trouble with List or Pointers, Adjacency Representaiton of Graph 
In createEdge() you have this:
e.start=v1;
e.start=v2;
Should it instead be
e.start=v1;
e.end=v2;
EDIT: Your problem is in createEdge, e1 and e2 are just copies, so changes
don't affect the actual vertex objects.
Here's my solution, seems to be working:
Add a function to vertex like so:
void addEdge(edge &e){edges.push_back(e);}
Then in createEdge():
edge e;
e.start=v1;
e.end=v2;
v1>addEdge(e);
v2>addEdge(e);

How to make formatted file read for Adjacency list? 
Use getline() to read each line into a string, and then construct
istringstream from the string and read numbers from there. Something like
this, but with better error checking.
std::ifstream file;
// open file etc.
std::string line;
AdjacencyList al;
while (!file.eof())
{
getline(file, line);
std::istringstream buffer(line);
int num;
buffer >> num;
auto it = al.insert(std::make_pair(num,
AdjacencyList::mapped_type()).first;
while (!buffer.eof())
{
buffer >> num;
it>push_back(num);
}
}

Problems with C++ Pointers, Iterator, Adjacency List Representation of Graph 
When calling addVertex(vertex * v), you add a copy of the vertex argument
to the list with graph.push_back(*v). Thus the vertex objects have
different addresses.
You probably want to store a std::list<vertex*> graph and use
graph.push_back(v), then.

Randomly choosing from a list with weighted probabilities 
The idea:
Iterate through all the elements and set the value of each element as the
cumulative frequency thus far.
Generate a random number between 1 and the sum of all frequencies
Do a binary search on the values for this number (finding the first value
greater than or equal to the number).
Example:
Element A B C D
Frequency 1 4 3 2
Cumulative 1 5 8 10
Generate a random number in the range 110 (1+4+3+2 = 10, the same as the
last value in the cumulative list), do a binary search, which will return
values as follows:
Number Element returned
1 A
2 B
3 B
4 B
5 B
6 C
7 C
8 C
9 D
10 D

Algorithm to convert adjacency list of a multigraph to an equivalent undirected graph 
If you want to achieve O(V+E) time complexity, there is no better
algorithm, because this is basically a variation of the element
distinctness problem, which can be solved by sorting in O(nlogn), or by
using O(n) extra space in O(n).
So, to achieve O(V+E) time, your algorithm is optimal (in terms of big O
notation)

Adjacency list of a undirected Graph is giving wrong ouptut in Java 
An adjacency matrix has every node in the head position and then all the
nodes connected to each head node in the secondaryList with edges relative
to the head node.
Vertex ver = findVertex(s);
if (ver == null)
{
ver = new Vertex(s);
this.vertices.add(ver);
}
ver.edgeLength = scan.nextInt();
from.connected.add(ver);
Seems like a problem.
Ideally every node in "vertices" (lets call it headList), should have 0
edgeLength (distance from itself).
You cannot pull a vertex from headList and push it in the
"connected"(secondaryList). The edgeLengths are realtive to the
headVertex for each secondaryList.

How to import a text file to a 3d matrix in matlab 
First, import your 2D matrix of coordinates/values into Matlab, possibly
using dlmread.
M = dlmread(filename, '/');
As noted by Shai you will want to convert the coordinates to 1offset
rather than 0offset:
M(:,1:3) = M(:,1:3) + 1;
Next, create an appropriately sized matrix to insert your values into.
foo = zeros(max(M(:,1)), max(M(:,2)), max(M(:,3)));
Finally, convert your your coordinates to indeces using sub2ind, and insert
the values.
idx = sub2ind(size(foo), M(:,1), M(:,2), M(:,3));
foo(idx) = M(:,4);

Pydev tags import as "unresolved import" but code using this import works fine. 
So, what you're seeing here is their distribution model. Usually a module
will have one root import that everything stems from, but that's not
necessarily the case. They're providing a package with (what I assume) is
many modules that don't interact with each other; or they can all stand
alone.
instead of importing each package individually, you could use the 'from'
keyword:
from ROOTFOL.PACKAGE import *
which will grab everything inside that submodule. You could email the
developer and ask why they deployed it this way...or you could add your own
__init__.py to the root folder and,
from ROOTFOL import *
which will walk the tree. Good luck!

Python strange import behavior: import x.y works, from x import y doesn't 
Works for me:
danielallan@MacBook:~$mkdir myproject
danielallan@MacBook:~$cd myproject/
danielallan@MacBook:myproject$mkdir lib
danielallan@MacBook:myproject$cd lib
danielallan@MacBook:lib$touch __init__.py
danielallan@MacBook:lib$touch view.py
danielallan@MacBook:lib$touch common_lib.py
danielallan@MacBook:lib$cd ..
In [1]: from lib import view
In [2]: view
Out[2]: <module 'lib.view' from 'lib/view.pyc'>
What happens when you try that on your machine? Are you sitting in the
wrong directory, or is your path not configured to find these files?

Import list into SQL 
If you have access to mysql command line then you could use the following
command:
LOAD DATA LOCAL INFILE '/path/myfile.txt' INTO TABLE mytable;
http://dev.mysql.com/doc/refman/5.0/en/loadingtables.html

How to convert a list into a matrix in R 
You can use unlist to get the values in the list, then use sapply to get
the number of values in each element of the list.
# Generate the list
a < list(1:10, 20:30, 40:45)
# Find the number of elements
num.el < sapply(a, length)
# Generate the matrix
res < cbind(unlist(a), rep(1:length(a), num.el))

R  How to return a list of matrix 
The error can be reproduced easily:
test < list(x=1, y=2)
test[[0]]
The problem is this:
1:21
#[1] 0 1
Maybe you want for(i in 1:(n1)){?

python 2D matrix simple logic works but matrix print logic doesnt show correct matrix 
You can use zip here:
>>> lis = [['a','b','c'],['d','e','f']]
>>> [ x[::1] for x in zip(*lis) ]
[('d', 'a'), ('e', 'b'), ('f', 'c')]
#or
>>> [ list(reversed(x)) for x in zip(*lis)]
[['d', 'a'], ['e', 'b'], ['f', 'c']]

Import a list from a different file 
One option is to dump that list into a temp file, and read it from your
other python script.
Another option (if one python script calls the other), is to pass the list
as an argument (e.g. using sys.argv[1] and *args, etc).

Create a matrix from a list of keyvalue pairs 
you probably have something like
m_dict = {'A': ['aa', 'bb', 'cc'], 'B': ['bb'], 'C': ['aa']}
i would go like this:
res = {}
for k, v in m_dict.items():
res[k] = defaultdict(int)
for col in v:
res[k][v] = 1
edit
given your format, it would probably be more in the line of :
m_array = [['A', 'aa'], ['A', 'bb'], ['A', 'cc'], ['B', 'bb'], ['C', 'aa']]
res = defaultdict(lambda: defaultdict(int))
for k, v in m_array:
res[k][v] = 1
which both give:
>>> res['A']['aa']
1
>>> res['B']['aa']
0

Matrix converting to a list in python 
from ast import literal_eval
with open('filename') as f:
lis = [[[abs(literal_eval(item))] for item in
line.rstrip('},
').lstrip('{').split(', ')] for line in f]
print lis
...
[[[0.00036], [1], [0], [1], [0], [0], [0], [0], [0], [0], [0], [0], [0],
[0], [0], [0], [0], [0], [0], [0], [0], [0], [0], [0]], [[0.0003],
[1.00026], [2], [0], [1], [0], [0], [0], [0], [0], [0], [0], [0], [0], [0],
[0], [0], [0], [0], [0], [0], [0], [0], [0]], [[0], [0.0002], [2], [0],
[0], [0], [0], [0], [0], [0], [0], [0], [0], [0], [0], [0], [0], [0], [0],
[0], [0], [0], [0], [0]]]

to convert a list to a 2D matrix in python 
Something like this:
>>> data = ['1,2','3,4']
>>> arr2=[ map(float,x.split(',')) for x in data]
>>> arr2 = np.asarray(arr2)
>>> A = np.asmatrix(arr2)
>>> A.I
matrix([[2. , 1. ],
[ 1.5, 0.5]])

Complex rearrangement of list into matrix 
library(reshape2)
table(melt(lst))
# L1
#value A B C D
# one 1 0 0 1
# three 1 0 0 0
# two 1 1 0 0
# five 0 1 0 1
# four 0 1 0 0
# seven 0 0 1 0
# six 0 0 1 0
# eight 0 0 0 1

How to feed values from a list of 9 elements to 3 by 3 matrix 
Use the grouper recipe to collect elements of L into groups of 3:
L = iter(L)
zip(*[L]*3)
For example,
In [11]: L = [11, 15, 18, 20, 22, 25, 30, 35, 40]
In [12]: L = iter(L)
In [13]: zip(*[L]*3)
Out[13]: [(11, 15, 18), (20, 22, 25), (30, 35, 40)]
I'm assuming by "matrix" you mean a list of tuples. It is easy to convert
this to a true matrix object (such as numpy.matrix) if that is what you
desire.
There is an explanation of the grouper recipe here.

Python Import txt file and having each line as a list 
Do not create separate lists; create a list of lists:
results = []
with open('inputfile.txt') as inputfile:
for line in inputfile:
results.append(line.strip().split(','))
or better still, use the csv module:
import csv
results = []
with open('inputfile.txt', newline='') as inputfile:
for row in csv.reader(inputfile):
results.append(row)
Lists or dictionaries are far superiour structures to keep track of an
arbitrary number of things read from a file.
Note that either loop also lets you address the rows of data individually
without having to read all the contents of the file into memory either;
instead of using results.append() just process that line right there.
Just for completeness sake, here's the oneliner compact version to read in
a CSV file into a li

list files in the sqoop import directory 
Without more details, I can't be sure, but maybe you're confused about
where the destination of the sqoop import is. Sqoop imports to the hadoop
filesystem, so to view the files, do the following:
hadoop fs ls
Here's some reference documentation:
http://hadoop.apache.org/docs/r0.18.3/hdfs_shell.html
It might be old, depending on the version of hadoop you're using.

Import Excel into SQL Server with ASP.NET MVC in a list so it will easy 
Have you considered using Linq to Excel? Pretty simple and straight forward
way to query data in your excel sheets using linq statements.
You could actually use nuget to add LinqToExcel to your MVC solution. Just
simply search for "LinqToExcel" and install the package.
After that's done your code would look something like this:
var excel = new ExcelQueryFactory();
excel.FileName = "PutFileNameHere";
var details = from x in excel.Worksheet<ExcelDate>() select x;
Then you could just loop through the contents of the collection "details"
and save that into your database.
foreach(var detail in details)
{
//add logic to save each line to your database
}
Here are some helpful links to get you started:
https://code.google.com/p/linqtoexcel/wiki/UsingLinqToExcel
https://code.g

How to cross check a python list of dictionaries against a csr matrix 
If X is your sparse matrix and
D = [{11998: 0.27257158100079237, 12114: 0.27024630707640002},
{10085: 0.23909781233007368, 9105: 0.57533007741289421},
{6577: 0.45085059256989168, 6491: 0.5895717192325539},
{5286: 0.4482789582819417, 6178: 0.32295433881928487}]
then
for i, d in enumerate(D):
for j in d:
d[j] = X[i, j]
gives the desired result:
>>> D
[{12114: 4.0, 11998: 2.0}, {9105: 8.0, 10085: 1.0}, {6577: 2.0, 6491: 4.0},
{6178: 8.0, 5286: 1.0}]


