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I have a list, which consists of several nested lists, and I want to extract first elements in each of this nested list and put as one single list. how to do this? {{{b->4.72971}},{{b->4...

gives the first n elements of list. Take [ list, - n] gives the last n elements of list. Take [ list, { m, n }] gives elements m through n of list. Take [ list, seq1, seq2, …] gives a nested list in which elements specified by seq i are taken at level i in list. Details Examples open all Basic Examples (6) Take the first 4 elements from a list:

Elements of Lists. The Wolfram Language provides a carefully chosen set of functions for accessing elements of lists using either indices or positions, or using patterns or criteria for their values. list [ [...]] ( Part) — parts of lists, resettable with =.

Lists allow you to treat any kind of collection of objects as a single entity. Sometimes you need to pick out or extract individual elements or groups of elements from a list. Set up a list of the first 10 squares (stored as v ): Copy to clipboard. Use Part to pick the third element of the list: Copy to clipboard.

Mathematica Stack Exchange is a question and answer site for users of Wolfram Mathematica. ... and I want to extract first elements in each of this nested list and ...

Lists can have any structure and size and can routinely involve even millions of elements. Well over a thousand built-in functions throughout the Wolfram ...

Take[list, n] gives the first n elements of list. Take[list, -n] gives ... gives a nested list in which elements specified by seqi are taken at level i in list.

It's also often useful to pick out columns in an array. Pick out the first column, by getting element 1 on all rows: In[12]:=. Click ...

This should be fast for large lists: Transpose[{Log @ #, #2} & @@ Transpose[#]] & @ list. {{-4.60517, 0.037348}, {-3.50656, 0.165434}, ...

Select, SelectFirst — select elements that satisfy a criterion. Cases, FirstCase — give elements ... MemberQ — test whether an element is a member of a list.

First[expr] gives the first element in expr. First[expr, def] gives the first element if it exists, or def otherwise.

Aug 27, 2011 · binarySearch = Compile[{{arg, _Integer}, {list, _Integer, 1}}, Module[ {min = 1, max = Length@list, i, x}, While[ min <= max, i = Floor[(min + max)/2]; x = list[[i]]; Which[ x == arg, min = max = i; Break[], x < arg, min = i + 1, True, max = i - 1 ] ]; If[ 0 == max, 0, max ] ], CompilationTarget -> "C", RuntimeOptions -> "Speed" ];

Get Elements of Lists. Lists are very important structures in the Wolfram Language. Lists allow you to treat any kind of collection of objects as a single entity. Sometimes you need to pick out or extract individual elements or groups of elements from a list. Set up a …

the i th element of list (the first element is list[[1]]) ... "Linear Algebra in Mathematica" discusses many other matrix operations that are built into the ...

Basic Examples (5)Summary of the most common use cases ... Extract the first element of a list: ... Extract the first row of a matrix: ... Extract the first element ...

Elements of Lists. The Wolfram Language provides a carefully chosen set of functions for accessing elements of lists using either indices or positions, or using patterns or criteria for their values. list [ [...]] ( Part) — parts of lists, resettable with =.

26.08.2011 · I changed the Ceiling function to a Floor function to correctly handle recurring elements in the list. It is needed because if the threshold is between elements n and n+1 then BinarySearch returns n+1/2.The code I wrote works perfectly, and does indeed return the first (leftmost) element which is greater than the threshold (the request was not for a matching …

First[expr] gives the first element in expr. First[expr, def] gives the first element if it exists, or def otherwise.

List Manipulation. Lists are central constructs in the Wolfram Language, used to represent collections, arrays, sets, and sequences of all kinds. Lists can have any structure and size and can routinely involve even millions of elements. Well over a thousand built-in functions throughout the Wolfram Language operate directly on lists, making ...

Lists are widely used in the Wolfram Language, and there are many ways to construct ... This takes elements up to the first element that is not less than 5:.

Sometimes you need to pick out or extract individual elements or groups of elements from a list. Set up a list of the first 10 squares (stored as v):.

Select does what you need, and will be consistent, respecting the pre-existing order of the list: Select[list, # > threshold &, 1].