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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
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Shuffle list items and make it random.
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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.
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Push List Items
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Splice a List
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Create the Empty List
Generate a list with no items.
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Print List Statistics
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