How to compact/rearrange a multi-dimensional array by removing null values

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valuesarray
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I have an array called $rows. The first row is the header. The first column is X (input signal), the other columns are Y1,Y2,Y3, etc. (output signals). For any X value some of Y values may be NULL. , Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers ,Making statements based on opinion; back them up with references or personal experience.

Input:

$rows = [
   ['X', 'Y1', 'Y2', 'Y3'],
   [.1, null, 10, null],
   [.5, 90, null, 7],
   [.7, 15, 40, null],
   [1.2, null, 12, null]
];
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88%

function sortByAge($a, $b) {
   return $a['age'] > $b['age'];
}
$people = [
   ["age" => 54, "first_name" => "Bob", "last_name" => "Dillion"],
   ["age" => 22, "first_name" => "Sarah", "last_name" => "Harvard"],
   ["age" => 31, "first_name" => "Chuck", "last_name" => "Bartowski"]
];

usort($people, 'sortByAge'); //$people is now sorted by age (ascending)
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Returns an array of values representing a single column from the input array. , A multi-dimensional array or an array of objects from which to pull a column of values from. If an array of objects is provided, then public properties can be directly pulled. In order for protected or private properties to be pulled, the class must implement both the __get() and __isset() magic methods. ,Example #3 Get the column of usernames from the public "username" property of an object ,array_column — Return the values from a single column in the input array

Array
   (
      [0] => John[1] => Sally[2] => Jane[3] => Peter
   )
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An array initializer for a 2D array contains the rows of A, separated by commas and enclosed between braces. Each row, in turn, is a list of values separated by commas and enclosed between braces. There are also 2D array literals with a similar syntax that can be used anywhere, not just in declarations. For example,,By the way, the standard function Arrays.copyOf() can't make a full copy of a 2D array in a single step. To do that, you need to copy each row separately. To make a copy of a two-dimensional array of int, for example:,This creates a 2D array of int that has 12 elements arranged in 3 rows and 4 columns. Although I haven't mentioned it, there are initializers for 2D arrays. For example, this statement creates the 3-by-4 array that is shown in the picture below:,It's easy enough to make a triangular array, if we create each row separately. To create a 7-by-7 triangular array of double, we can use the code segment

Two-dimensional arrays were introduced in Subsection 3.8.5, but we haven't done much with them since then. A 2D array has a type such as int[][] or String[][], with two pairs of square brackets. The elements of a 2D array are arranged in rows and columns, and the new operator for 2D arrays specifies both the number of rows and the number of columns. For example,

int[][] A;
A = new int[3][4];
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Last Updated : 19 Jul, 2021,Difficulty Level : Easy,Given an array of size n and a number k, find all elements that appear more than n/k times,Given an array of random numbers, Push all the zero’s of a given array to the end of the array. For example, if the given arrays is {1, 9, 8, 4, 0, 0, 2, 7, 0, 6, 0}, it should be changed to {1, 9, 8, 4, 2, 7, 6, 0, 0, 0, 0}. The order of all other elements should be same. Expected time complexity is O(n) and extra space is O(1).Example:  

Given an array of random numbers, Push all the zero’s of a given array to the end of the array. For example, if the given arrays is {1, 9, 8, 4, 0, 0, 2, 7, 0, 6, 0}, it should be changed to {1, 9, 8, 4, 2, 7, 6, 0, 0, 0, 0}. The order of all other elements should be same. Expected time complexity is O(n) and extra space is O(1).
Example: 
 

Input: arr[] = {
   1,
   2,
   0,
   4,
   3,
   0,
   5,
   0
};
Output: arr[] = {
   1,
   2,
   4,
   3,
   5,
   0,
   0,
   0
};

Input: arr[] = {
   1,
   2,
   0,
   0,
   0,
   3,
   6
};
Output: arr[] = {
   1,
   2,
   3,
   6,
   0,
   0,
   0
};

Array after pushing all zeros to end of array:
   1 9 8 4 2 7 6 9 0 0 0 0
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3.2 Multidimensional arrays,3.1 One-dimensional arrays,3 Element identifier and addressing formulas 3.1 One-dimensional arrays 3.2 Multidimensional arrays 3.3 Dope vectors 3.4 Compact layouts 3.5 Resizing 3.6 Non-linear formulas ,Articles with MA identifiers

In computer science, an array data structure, or simply an array, is a data structure consisting of a collection of elements (values or variables), each identified by at least one array index or key. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula.[1][2][3] The simplest type of data structure is a linear array, also called one-dimensional array.

For example, an array of 10 32-bit (4-byte) integer variables, with indices 0 through 9, may be stored as 10 words at memory addresses 2000, 2004, 2008, ..., 2036, (in hexadecimal: 0x7D0, 0x7D4, 0x7D8, ..., 0x7F4) so that the element with index i has the address 2000 + (i × 4).[4]

0x7D0

In computer science, an array data structure, or simply an array, is a data structure consisting of a collection of elements (values or variables), each identified by at least one array index or key. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula.[1][2][3] The simplest type of data structure is a linear array, also called one-dimensional array.

For example, an array of 10 32-bit (4-byte) integer variables, with indices 0 through 9, may be stored as 10 words at memory addresses 2000, 2004, 2008, ..., 2036, (in hexadecimal: 0x7D0, 0x7D4, 0x7D8, ..., 0x7F4) so that the element with index i has the address 2000 + (i × 4).[4]

0x7D4

In computer science, an array data structure, or simply an array, is a data structure consisting of a collection of elements (values or variables), each identified by at least one array index or key. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula.[1][2][3] The simplest type of data structure is a linear array, also called one-dimensional array.

For example, an array of 10 32-bit (4-byte) integer variables, with indices 0 through 9, may be stored as 10 words at memory addresses 2000, 2004, 2008, ..., 2036, (in hexadecimal: 0x7D0, 0x7D4, 0x7D8, ..., 0x7F4) so that the element with index i has the address 2000 + (i × 4).[4]

0x7D8

In computer science, an array data structure, or simply an array, is a data structure consisting of a collection of elements (values or variables), each identified by at least one array index or key. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula.[1][2][3] The simplest type of data structure is a linear array, also called one-dimensional array.

For example, an array of 10 32-bit (4-byte) integer variables, with indices 0 through 9, may be stored as 10 words at memory addresses 2000, 2004, 2008, ..., 2036, (in hexadecimal: 0x7D0, 0x7D4, 0x7D8, ..., 0x7F4) so that the element with index i has the address 2000 + (i × 4).[4]

0x7F4
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