Removing duplicate rows in vi?
If you’re OK with sorting your file, you can use: :sort u
duplicates
Finding ALL duplicate rows, including “elements with smaller subscripts”
duplicated has a fromLast argument. The “Example” section of ?duplicated shows you how to use it. Just call duplicated twice, once with fromLast=FALSE and once with fromLast=TRUE and take the rows where either are TRUE. Some late Edit: You didn’t provide a reproducible example, so here’s an illustration kindly contributed by @jbaums vec <- c(“a”, … Read more
Does adding a duplicate value to a HashSet/HashMap replace the previous value
In the case of HashMap, it replaces the old value with the new one. In the case of HashSet, the item isn’t inserted.
Regular expression for duplicate words
Try this regular expression: \b(\w+)\s+\1\b Here \b is a word boundary and \1 references the captured match of the first group. Regex101 example here
How do I remove duplicate items from an array in Perl?
You can do something like this as demonstrated in perlfaq4: sub uniq { my %seen; grep !$seen{$_}++, @_; } my @array = qw(one two three two three); my @filtered = uniq(@array); print “@filtered\n”; Outputs: one two three If you want to use a module, try the uniq function from List::MoreUtils
How to delete duplicates on a MySQL table?
This removes duplicates in place, without making a new table. ALTER IGNORE TABLE `table_name` ADD UNIQUE (title, SID) Note: This only works well if index fits in memory.
How to “select distinct” across multiple data frame columns in pandas?
You can use the drop_duplicates method to get the unique rows in a DataFrame: In [29]: df = pd.DataFrame({‘a’:[1,2,1,2], ‘b’:[3,4,3,5]}) In [30]: df Out[30]: a b 0 1 3 1 2 4 2 1 3 3 2 5 In [32]: df.drop_duplicates() Out[32]: a b 0 1 3 1 2 4 3 2 5 You can … Read more
How to get duplicate items from a list using LINQ? [duplicate]
var duplicates = lst.GroupBy(s => s) .SelectMany(grp => grp.Skip(1)); Note that this will return all duplicates, so if you only want to know which items are duplicated in the source list, you could apply Distinct to the resulting sequence or use the solution given by Mark Byers.
In MySQL, can I copy one row to insert into the same table?
I used Leonard Challis’s technique with a few changes: CREATE TEMPORARY TABLE tmptable_1 SELECT * FROM table WHERE primarykey = 1; UPDATE tmptable_1 SET primarykey = NULL; INSERT INTO table SELECT * FROM tmptable_1; DROP TEMPORARY TABLE IF EXISTS tmptable_1; As a temp table, there should never be more than one record, so you don’t … Read more
Removing duplicate rows from table in Oracle
Use the rowid pseudocolumn. DELETE FROM your_table WHERE rowid not in (SELECT MIN(rowid) FROM your_table GROUP BY column1, column2, column3); Where column1, column2, and column3 make up the identifying key for each record. You might list all your columns.