duplicate-removal | 易学教程

Delete Duplicate email addresses from Table in MYSQL

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问题 I have a table with columns for ID , firstname , lastname , address , email and so on. Is there any way to delete duplicate email addresses from the TABLE? Additional information (from comments): If there are two rows with the same email address one would have a normal firstname and lastname but the other would have 'Instant' in the firstname . Therefore I can distinguish between them. I just want to delete the one with first name 'instant'. Note, some records where the firstname='Instant'

Remove all duplicates except last instance

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So I have a dataset in R with the following layout as an example: ID Date Tally 1 2/1/2011 1 2 2/1/2011 2 3 2/1/2011 3 1 2/1/2011 4 2 2/1/2011 5 1 2/1/2011 6 3 2/1/2011 7 4 2/1/2011 8 2 2/1/2011 9 I want to remove all instances except the LAST instance of the post id. Right now everything I can find online, and functions I am using is removing everything except the FIRST instance. So my new data frame would look like: ID Date Tally 1 2/1/2011 6 3 2/1/2011 7 4 2/1/2011 8 2 2/1/2011 9 How do I do this? Right now I am only able to keep the first instance. I want it to do the opposite? Any help?

mongo 3 duplicates on unique index - dropDups

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问题 In the documentation for mongoDB it says: "Changed in version 3.0: The dropDups option is no longer available." Is there anything I can do (other than downgrading) if I actually want to create a unique index and destroy duplicate entries? please keep in mind the I receive about 300 inserts per second so I can't just delete all duplicates and hope none will come in by the time I'm done indexing. 回答1: Yes dropDupes is now deprecated since version 2.7.5 because it was not possible to predict

How to delete duplicates in SQL table based on multiple fields

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I have a table of games, which is described as follows: +---------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------+-------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | date | date | NO | | NULL | | | time | time | NO | | NULL | | | hometeam_id | int(11) | NO | MUL | NULL | | | awayteam_id | int(11) | NO | MUL | NULL | | | locationcity | varchar(30) | NO | | NULL | | | locationstate | varchar(20) | NO | | NULL | | +---------------+-------------+------+-----+-----

Deleting rows that are duplicated in one column based on the conditions of another column

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问题 Here is an example of my data set; Date Time(GMT)Depth Temp Salinity Density Phosphate 24/06/2002 1000 1 33.855 0.01 24/06/2002 1000 45 33.827 0.01 01/07/2002 1000 10 13.26 33.104 24.873 0.06 01/07/2002 1000 30 12.01 33.787 25.646 0.13 08/07/2002 1000 5 13.34 33.609 25.248 0.01 08/07/2002 1000 40 12.01 34.258 26.011 1.33 15/07/2002 1000 30 12.04 34.507 26.199 0.01 22/07/2002 1000 5 13.93 33.792 25.269 0.01 22/07/2002 1000 30 11.9 34.438 26.172 0.08 29/07/2002 1000 5 13.23 34.09 25.642 0.01 I

How to remove duplicate entries from a mysql db?

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I have a table with some ids + titles. I want to make the title column unique, but it has over 600k records already, some of which are duplicates (sometimes several dozen times over). How do I remove all duplicates, except one, so I can add a UNIQUE key to the title column after? unutbu This command adds a unique key, and drops all rows that generate errors (due to the unique key). This removes duplicates. ALTER IGNORE TABLE table ADD UNIQUE KEY idx1(title); Edit: Note that this command may not work for InnoDB tables for some versions of MySQL. See this post for a workaround. (Thanks to "an

Remove duplicate CSS declarations across multiple files

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问题 I'm looking to remove duplicate CSS declarations from a number of files to make implementing changes easier. Is there a tool that can help me do that? Right now I'm faced with something like this: styles.css #content { width:800px; height:1000px; background: green; } styles.game.css #content { width:800px; height:1000px; background: blue; } And I want this: styles.css #content { width:800px; height:1000px; background: green; } styles.game.css #content { background: blue; } The total number of

Remove duplicates from an array based on object property?

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问题 I have an array of objects. I'd like to remove the duplicates based on the "name" value in the object. [0]=> object(stdClass)#337 (9) { ["term_id"]=> string(2) "23" ["name"]=> string(12) "Assasination" ["slug"]=> string(12) "assasination" } [1]=> object(stdClass)#44 (9) { ["term_id"]=> string(2) "14" ["name"]=> string(16) "Campaign Finance" ["slug"]=> string(16) "campaign-finance" } [2]=> object(stdClass)#298 (9) { ["term_id"]=> string(2) "15" ["name"]=> string(16) "Campaign Finance" ["slug"]

Techniques for finding near duplicate records

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I'm attempting to clean up a database that, over the years, had acquired many duplicate records, with slightly different names. For example, in the companies table, there are names like "Some Company Limited" and "SOME COMPANY LTD!". My plan was to export the offending tables into R, convert names to lower case, replace common synonyms (like "limited" -> "ltd"), strip out non-alphabetic characters and then use agrep to see what looks similar. My first problem is that agrep only accepts a single pattern to match, and looping over every company name to match against the others is slow. (Some

python remove duplicates from 2 lists

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问题 I am trying to remove duplicates from 2 lists. so I wrote this function: a = ["abc", "def", "ijk", "lmn", "opq", "rst", "xyz"] b = ["ijk", "lmn", "opq", "rst", "123", "456", ] for i in b: if i in a: print "found " + i b.remove(i) print b But I find that the matching items following a matched item does not get remove. I get result like this: found ijk found opq ['lmn', 'rst', '123', '456'] but i expect result like this: ['123', '456'] How can I fix my function to do what I want? Thank you. 回答1