duplicates

问题 I want to remove duplicates from this list: List<Dictionary<string, object>> val = new List<Dictionary<string, object>>(); It does not work if I apply Distinct() in this way: List<Dictionary<string, object>> result = val.Distinct().ToList<Dictionary<string, object>>() Update: Problem is now solved. I used the MySQL union command to read table from the database. 回答1: Try this: List<Dictionary<string, object>> result = val.Distinct(new myDictionaryComparer()).ToList(); where

问题 I ran into a problem regarding set in Python 2.7. Here's the appropriate example code block: letters = set(str(raw_input("Type letters: "))) As you can see, the point is to write some letters to assign to "letters" for later use. But if I type "aaabbcdd", the output of "letters" returns set(['a', 'c', 'b', 'd']) My question is how to write the code, so that the output will allow duplicates like this: set(['a','a','a','b','b','c','d','d']) ? 回答1: set doesn't store duplicates, which is why it's

问题 I have two list views that are fragments in view pager tabs. When you click on the items in the list view it launches a new activity. But when I press the back-button to get back to the tabbed list view, the list view has doubled and if I open the activity and go back again it doubles again and it will keep doing that. Also I have another tabbed list view with five tabs and when I go two tabs away from one of the views. The items in that view double when I come back to them and this is the

问题 this is my code: var header1: Record? = null var header2: Record? = null header2 = header1 header2.name = "new_name" but header1.name changes too! 回答1: You are just assigning the same object (same chunk of memory) to another variable. You need to somehow crate new instance and set all fields. header2 = Record() header2.name = header1.name However in Kotlin, if the Record class was Data class, Kotlin would create a copy method for you. data class Record(val name: String, ...) ... header2 =

问题 What would be the best way to remove duplicates while merging their records into one? I have a situation where the table keeps track of player names and their records like this: stats ------------------------------- nick totalgames wins ... John 100 40 john 200 97 Whistle 50 47 wHiStLe 75 72 ... I would need to merge the rows where nick is duplicated (when ignoring case) and merge the records into one, like this: stats ------------------------------- nick totalgames wins ... john 300 137

问题 If you have an URL like this: Java lib or app to convert CSV to XML file? If someone creates a link on his website, but changes the name like this Java lib or app to convert CSV to XML file? that would cause duplicate content. Is it nessecary to check if the name in the url is the same as the real name of the question and if not do a 301 redirect to the correct URL? I see Stackoverflow.com doesn't do a 301 redirect, but just accepts any name in the URL. Can this cause duplicate content or

问题 I have an SQL table: +-------------+-----------+---------+ | ID | position | user | +-------------+-----------+---------+ | 1 | 1 | 0 | | 2 | 2 | 0 | | 3 | 3 | 0 | | 4 | 4 | 0 | | 5 | 5 | 0 | | 6 | 6 | 0 | | 7 | 7 | 0 | | 8 | 7 | 1 | +-------------+-----------+---------+ I would like to filter the duplicate row based on position column and the distinct value of user column, for the first query I need to have the following result: +-------------+-----------+---------+ | ID | position | user |

问题 I have a loop in which I calculate a value and add it it a list. So, I do something like that: x = getValue() values.add(x) while (true) { x = getValue(); values.add(x) } I found out that this approach does not work since I add the same instance to the list. In more details, in every cycle of the loop I re-assign a new value to the x and doing so I change values of all elements that were already added to the list (so in the end I get a list of identical elements). To solve this problem I did

问题 I am searching for sortable (I mean sorting after initialization and many times using Comparator) Java class collection without duplicates. Is there any more pure solution than writing code which will opaque and prevent for example some ArrayList for adding another object with the same value that already exists? Edit 1: I should add some explanation about sorting. I need to sort this set of values many times with different comparators (diversity of implementations). 回答1: Use a Set! The common

问题 Consider I have this string 'aaaabbbaaaaaabbbb' I want to convert this to array so that I get the following result $array = [ 'aaaa', 'bbb', 'aaaaaa', 'bbbb' ] How to go about this in PHP? 回答1: I have written a one-liner using only preg_split() that generates the expected result with no wasted memory (no array bloat): Code (Demo): $string='aaaabbbaaaaaabbbb'; var_export(preg_split('/(.)\1*\K/',$string,NULL,PREG_SPLIT_NO_EMPTY)); Output: array ( 0 => 'aaaa', 1 => 'bbb', 2 => 'aaaaaa', 3 =>