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Duplicate list item finder

World's simplest list tool

This is a super simple browser-based application that finds duplicate items in a list. If an item appears in a list more than once, then the program will print it in the output area. Depending on the output mode, it can print each duplicate one time or as many times as they are repeated. You can also skip all empty items and remove surrounding whitespaces. Created by list geeks from team Browserling.
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Item Boundaries
Select this option if the item boundary is a symbol or multiple symbols. (Enter symbols below.)
Select this option if the item boundary is different symbols or patterns. (Enter regex below.)
Enter item boundary symbol or regex. For example, "," or /-{1,2}/.
Duplicate Search Settings
Output each duplicate item only once.
Output all repeated copies of items.
Output Separator and Trimming
Use this symbol to separate items in the duplicate list.
Delete all leading and trailing whitespaces from the list items.
Ignore all items that have zero length.
Duplicate list item finder tool What is a duplicate list item finder?
With this utility, you can find repeated items in any list. The program runs through all items in the input list and checks if the current item has been seen before. Duplicate items that appear in the list more than once are returned to the screen. By default, each duplicate item is returned to the screen only once. For example, if the input list is "a, b, a, a, c, c", then the output list is "a, c". You can change the duplicate report mode and display all item copies to the screen. In this case, the output for the list "a, b, a, a, c, c" will be "a, a, c". The input items can be numbers, words, strings, symbols, and other glyphs. To correctly find item boundaries in a list, you can use the option for separating items by a character or a regular expression. Just select the split format that your list uses and enter the character or regular expression in the item boundary delimiter field. To get a consistent and well-formatted list in the output, you can set a constant separator for the output list of duplicates. By default, the trim items option is also enabled. This option controls the spaces at the beginning and end of items. If two items differ only by spaces at the beginning or end, then they are considered to be equal items. And another option that's enabled controls empty items. If an item has zero length then it's considered to be an empty item and is not displayed in the output. Listabulous!
Duplicate list item finder examples Click to use
List of Clothes
In this example, we find duplicate clothes in a shopping list. Each garment that has been listed more than once is displayed on the screen. To skip displaying empty items, we have activated the "Remove Empty Items" option. The other option "Trim List Items" is activated as well. As the input list of clothes is comma-separated, we use a single character boundary mode to extract the items and set the boundary character to a comma. In the output, we print each item on a new line, using the character "\n" as a separator.
jacket, scarf ,, coat, skirt, pants,, shirt , dress, hat, socks, pants, dress, shirt, , coat, suit, socks, jeans, hat, slacks, hat, jeans, jeans
pants dress shirt coat socks hat jeans
Required options
These options will be used automatically if you select this example.
Select this option if the item boundary is a symbol or multiple symbols. (Enter symbols below.)
Enter item boundary symbol or regex. For example, "," or /-{1,2}/.
Output each duplicate item only once.
Use this symbol to separate items in the duplicate list.
Delete all leading and trailing whitespaces from the list items.
Ignore all items that have zero length.
List of Control Characters
This example finds and extracts all repeating items in a list of ASCII control characters. Since the input list has the TSV format (tab-separated values), we use the regular expression "/\s/" to separate items by tabs and accidental spaces. The program displays all repeating control characters exactly as many times as they repeat and separates them with a space character.
NUL NUL SOH STX ETX ETX ETX EOT ENQ ENQ ENQ ENQ ACK BEL BS BS BS TAB TAB TAB LF VT FF FF CR SO SI SI DEL DLE DC1 DC1 DC1 DC2 DC3 DC4 DC4 NAK SYN SYN ETB CAN EM EM SUB SUB SUB ESC ESC FS GS RS RS US
NUL ETX ETX ENQ ENQ ENQ BS BS TAB TAB FF SI DC1 DC1 DC4 SYN EM SUB SUB ESC RS
Required options
These options will be used automatically if you select this example.
Select this option if the item boundary is different symbols or patterns. (Enter regex below.)
Enter item boundary symbol or regex. For example, "," or /-{1,2}/.
Output all repeated copies of items.
Use this symbol to separate items in the duplicate list.
Delete all leading and trailing whitespaces from the list items.
Ignore all items that have zero length.
List of Banknote Glyphs
The list in this example is made from banknote symbols and the delimiter character is a tilde. To find duplicate list elements, we first split the input data by the tilde character via the "Boundary is a Symbol" mode. Then we clean up all spaces that surround the banknotes via the "Trim List Items" option. We find the unique banknote duplicates and print them in a new semicolon character-separated list.
€ ~ ¥ ~ ₹ ~ ₽ ~ € ~ € ~ £ ~ ₩ ~ ฿ ~ ฿ ~ £ ~ ฿ ~ $ ~ $ ~ ₺ ~ ¥ ~ ₺ ~ ₴ ~ ₩ ~ ₹ ~ €
€; ฿; $; ¥; ₺; ₹
Required options
These options will be used automatically if you select this example.
Select this option if the item boundary is a symbol or multiple symbols. (Enter symbols below.)
Enter item boundary symbol or regex. For example, "," or /-{1,2}/.
Output each duplicate item only once.
Use this symbol to separate items in the duplicate list.
Delete all leading and trailing whitespaces from the list items.
Ignore all items that have zero length.
Pro tips Master online list tools
You can pass input to this tool via ?input query argument and it will automatically compute output. Here's how to type it in your browser's address bar. Click to try!
https://onlinelisttools.com/find-duplicate-list-items?input=jacket%2C%20scarf%20%2C%2C%20coat%2C%20skirt%2C%20pants%2C%2C%20shirt%20%2C%20dress%2C%20hat%2C%20socks%2C%20pants%2C%20dress%2C%20shirt%2C%20%2C%20coat%2C%20suit%2C%20socks%2C%20jeans%2C%20hat%2C%20slacks%2C%20hat%2C%20jeans%2C%20jeans&string-separator=true&input-separator=%2C&output-separator=%5Cn&trim-elements=true&skip-empty=true&print-unique-duplicates=true
All list tools
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Quickly print all distinct items of a list.
Quickly print all repeating items of a list.
Quickly count the number of items in a list.
Quickly find certain items in a list.
Quickly print all list items in reverse order.
Quickly sort list items alphabetically or numerically.
Quickly shuffle list items and make it random.
Quickly randomly pick one or more items from a list.
Quickly create a downloadable image from a list.
Quickly display list items in multiple colors.
Quickly set a new delimiter for items in a list.
Quickly remove the symbol that separates list items.
Quickly change list item delimiters to the same symbol.
Quickly remove items from the beginning or end of a list.
Quickly join all items of a list together.
Quickly create groups of multiple list items.
Quickly extract a part of a list.
Quickly remove all empty items from a list.
Quickly remove whitespace characters around list items.
Quickly create multiple copies of a list.
Quickly rotate list items to the left or right (or up and down).
Quickly enumerate list items and add a counter to them.
Quickly add bullet markers to all items in a list.
Quickly wrap all list items in quotes.
Quickly remove all quotation marks from around list items.
Quickly add text on the left and right sides of all list items.
Quickly remove text from the left and right sides of all list items.
Quickly prepend a prefix before each list item.
Quickly delete any prefix from the beginning of all list items.
Quickly append a suffix after each list item.
Quickly delete any suffix from the end of all list items.
Quickly add or remove list items to make it a certain length.
Quickly create multiple columns from a single list.
Quickly create a palindromic list from the given list.
Quickly generate a list of arbitrary length with arbitrary items.
Quickly generate a random length list with random items.
Quickly add new items at the beginning or end of a list.
Quickly left-pad a list with one or more items.
Quickly right-pad a list with one or more items.
Quickly analyze a list and print its item statistics.
Coming soon These list tools are on the way
Edit a List
View and edit lists in a neat browser-based list editor.
Split a List
Split list items into chunks.
Generate the Powerlist
Create the powerlist of the given list.
Find the Car of a List
Extract the first item from a list.
Find the Cdr of a List
Extract all items except the first of a list.
Apply a Function on a List
Run a JavaScript function on every list item.
Delete List Item
Quickly remove certain items from a list.
Find Certain List Items
Quickly find and print items that interest you in a list.
Find Non-repeating List Items
Quickly find and print items that don't repeat in a list.
Find Repeating List Items
Quickly find and print items that repeat in a list.
Delete Repeating List Items
Quickly find and remove items that repeat in a list.
Delete Unique List Items
Quickly find and remove items that are unique in a list.
Extract a Sublist from a List
Given start and stop indexes, extract a sublist from a list.
Shift List Items
Shift list items to the left or right (or up and down).
Indent List Items
Add indentation to all list items.
Mirror a List
Quickly create a mirror copy of a list.
Invert a List
Invert the order of items in a list (last becomes first, etc).
Reduce a List
Run the reduce function on a list.
Convert a List to Rows
Create multiple rows from a single list.
Convert a List to Excel
Create an Excel file from a list.
Convert a List to PDF
Create a PDF file from a list.
Convert a Text List to a LaTeX List
Create a LaTeX list from a regular text list.
Convert a Text List to a HTML List
Create a HTML list from a regular text list.
Convert a Text List to a Markdown List
Create a Markdown list from a regular text list.
Compare Two Lists
Find the difference between two lists.
Compare Three Lists
Find the difference between three lists.
Remove One List from Another
Remove elements from a list that appear in the other list.
Zip Two Lists
Join two lists together item by item.
Merge Two Lists
Append a second list at the end of the first list.
Pair List Items
Create pairs from all list items.
Pop List Items
Remove list items at certain index positions.
Push List Items
Add new items at the end of a list.
Replace List Items
Replace certain items in a list with new items.
Splice a List
Modify a list in-place by adding, replacing, or removing items.
Flatten a List
Remove all indentation levels from a list and make it flat.
Make List Items Title Case
Quickly change the letter case of all items to title case.
Make List Items Proper Case
Quickly change the letter case of all items to proper case.
Make List Items Random Case
Quickly randomly change the letter case of all items.
Make List Items Lowercase
Quickly change the letter case of all items to small letters.
Make List Items Uppercase
Quickly change the letter case of all items to capital letters.
Remove List Item Bullets
Quickly remove any bullet marks before items in a list.
Remove List Item Counter
Quickly remove any numeration from a list of items.
Create the Empty List
Generate a list with no items.
Visualize a List
Quickly create a graphical representation of a list.
Create a List Cloud
Create an image with a cloud of list items.
Let Zalgo Destroy a List
Let Zalgo loose on a list and create list-chaos.