duplicates | 易学教程

Remove duplicate items from an array

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I use the line of code below to loop through a table in my database: $items_thread = $connection -> fetch_all($sql); And if I print the array out: print_r($items_thread); I will get this: Array ( [0] => Array ( [RecipientID] => 3 [RecipientScreenname] => Tom L [RecipientFirstname] => Thomas [RecipientEmail] => info@xx.com ) [1] => Array ( [RecipientID] => 3 [RecipientScreenname] => Tom L [RecipientFirstname] => Thomas [RecipientEmail] => info@xx.com ) [2] => Array ( [RecipientID] => 1 [RecipientScreenname] => Lau T [RecipientFirstname] => TK [RecipientEmail] => lau@xx.co.uk ) ) But I want to

How to allow duplicate keys in php array [duplicate]

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问题 This question already has answers here : PHP Associative Array Duplicate Keys (5 answers) Closed 4 years ago . How to allow php array to have duplicate keys? When I try to insert a key, value pair with already existing key it overwrites the value of corresponding previous key with the new value. Is there a way that I could maintain both duplicate keys having different values? 回答1: You could have a single key that has a value of an array(aka a multi-dimensional array), which would contain all

Finding duplicate values in arraylist

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I have an ArrayList<Car> For Example class Car{ String carName; int carType; } Now, I have to find if the list has any cars having same name. What is the best way to do this? Swaranga Sarma Create a comparator: public class CarComparator implements Comparator<Car> { public int compare(Car c1, Car c2) { return c1.carName.compareTo(c2.carName); } } Now add all the cars of the ArrayList to a SortedSet , preferably TreeSet ; if there are duplicates add to the list of duplicates: List<Car> duplicates = new ArrayList<Car>(); Set<Car> carSet = new TreeSet<Car>(new CarComparator()); for(Car c :

php/mysql prevent duplicate entries over multiple columns

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问题 I would like to come up with a standard practice to prevent any tables from having duplicates where it matters. In most cases duplicates are a combination of variables rather than one. My primary keys are just the unique ids for each field so I cannot use them. What I have been doing is querying the table first and then if the number of rows for the combination in question is 0, making the insert. However, I have read it should be possible to set up a unique key over multiple fields to

Display duplicate records in data.frame and omit single ones

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问题 I have been struggling with how to select ONLY duplicated rows of data.frame in R. For Instance, my data.frame is: age=18:29 height=c(76.1,77,78.1,78.2,78.8,79.7,79.9,81.1,81.2,81.8,82.8,83.5) Names=c("John","John","John", "Harry", "Paul", "Paul", "Paul", "Khan", "Khan", "Khan", "Sam", "Joe") village <- data.frame(Names, age, height) Names age height John 18 76.1 John 19 77.0 John 20 78.1 Harry 21 78.2 Paul 22 78.8 Paul 23 79.7 Paul 24 79.9 Khan 25 81.1 Khan 26 81.2 Khan 27 81.8 Sam 28 82.8

Comparing two Lists and returning the distinct values and the differences

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问题 I have two lists: List A {A, B, C, D} List B {A, E, F, G} I need to produce three lists: One with the items only in list A (B, C, D) One with the items only in list B (E, F, G) One with the items in both (A) Given that the lists are actually registry keys, there could be a huge number of them so I can foresee a huge performance overhead if I choose to use traditional ForEach or For(int i...) methods. I am not averse to these if they will do the job efficiently but I would prefer to use Linq.

Identify duplicates and mark first occurrence and all others

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问题 I'm trying to identify all rows which are represented twice or more in a matrix. For example: m <- matrix(c(1,2,1,3,1,4,1,2,2,3,2,3,1,2,5), ncol = 3) m duplicated(m[,1]) Outputs: [,1] [,2] [,3] [1,] 1 4 2 [2,] 2 1 3 [3,] 1 2 1 [4,] 3 2 2 [5,] 1 3 5 [1] FALSE FALSE TRUE FALSE TRUE However, I do not want that output. I want: [1] TRUE FALSE TRUE FALSE TRUE since row[1,1]'s value appears 3 times in m's column 1. 回答1: When I saw this question I asked myself "what would Jim Holtman or Bill Dunlap

Excel VBA - Combine rows with duplicate values in one cell and merge values in other cell

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I am trying to find duplicate values in one column and combine the values of a second column into one row. I also want to sum the values in a third column. For example: A B C D h 4 w 3 h 4 u 5 h 4 g 7 h 4 f 4 k 9 t 6 k 9 o 6 k 9 p 9 k 9 j 1 Would become A B C D k 9 t;o;p;j 22 h 4 w;u;g;f 19 The code I have been using for the first part of this is Sub mergeCategoryValues() Dim lngRow As Long With ActiveSheet lngRow = .Cells(65536, 1).End(xlUp).Row .Cells(1).CurrentRegion.Sort key1:=.Cells(1), Header:=xlYes Do If .Cells(lngRow, 9) = .Cells(lngRow + 1, 9) Then .Cells(lngRow, 11) = .Cells(lngRow,

Remove duplicate characters from string

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问题 I have to make a function in JavaScript that removes all duplicated letters in a string. So far I've been able to do this: If I have the word "anaconda" it shows me as a result "anaconda" when it should show "cod". Here is my code: function find_unique_characters( string ){ var unique=''; for(var i=0; i<string.length; i++){ if(unique.indexOf(string[i])==-1){ unique += string[i]; } } return unique; } console.log(find_unique_characters('baraban')); 回答1: We can also now clean things up using

How can I remove duplicate words in a string with Python?

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Following example: string1 = "calvin klein design dress calvin klein" How can I remove the second two duplicates "calvin" and "klein" ? The result should look like string2 = "calvin klein design dress" only the second duplicates should be removed and the sequence of the words should not be changed! def unique_list(l): ulist = [] [ulist.append(x) for x in l if x not in ulist] return ulist a="calvin klein design dress calvin klein" a=' '.join(unique_list(a.split())) string1 = "calvin klein design dress calvin klein" words = string1.split() print (" ".join(sorted(set(words), key=words.index)))