The Join ()() block is an Operators block and a Reporter block. The block concatenates, or "links" the two values together and reports the result — for example, if "hello" and "world" were put in the block, it would report "helloworld". To report "hello world", use either "hello " and "world" or "hello" and " world", with a space.
To join three or more values together, put this block inside one of its inputs.
If words, numbers, sentences—any two values—must be concatenated together, this block easily does the job.
Some common uses for the Join ()() block:
- Joining words and variables to create a sentence
when flag clicked ask [What's your name?] and wait say (join (join (join (join [Hello ] (answer))[. My name is ]) (Person's name)) [.])
- Place a variable in a message (e.g. "You completed 2 loops")
say (join [The score is ] (join (score) [.]))
- An easy method of negating a positive number
set [variable v] to (join [-] (number))
|Note:||This does not work on numbers that are already negative.|
- Using hex inputs in pen colors
set pen color to (join [0x] (hex input))
Offline decimal trick
In the Offline Editor (this does not work online!), numbers in variables and speech bubbles usually round to only one decimal place. In some projects, it is necessary to have more. Placing the calculation in one input of the Join ()() block and leaving the other input empty "magically" reports the number with more decimal places.
- The original script:
set [number v] to ([sqrt v] of ((item (1 v) of [list v]) * (3)))
- Script with more decimals:
set [number v] to (join([sqrt v] of ((item (1 v) of [list v]) * (3))) )
- To set the number of decimal places, use a script like this:
set [number v] to (join((round (([10^ v] of (decimal places)::operators) * ([sqrt v] of ((item (1 v) of [list v]) * (3))))) / ([10^ v] of (decimal places)::operators)))
- Main article: List of Block Workarounds
This block can be replicated with the following code:
delete all of [final v] set [count v] to  repeat (length of (insert1)) change [count v] by (1) add (letter (count) of (insert1)) to [final v] end set [count v] to  repeat (length of (insert2)) change [count v] by (1) add (letter (count) of (insert2)) to [final v] end set [result v] to (final)
The variable "result" contains the result. This works because list reporters join all of the items in a list without spaces if they are all 1 character long, and so by taking just 1 letter from each string at a time and putting them into the list, the reporter has the same result as the join block in most cases.
The join block displays a phenomenon where it does not output strings longer than 10240 characters, even if either side or both sides of the concatenation are longer than this amount. The characters which are expected to appear beyond the 10240th character are just truncated. It is still possible to join two strings to longer than 10240, but it cannot be done with the join block — it must be done using the workaround listed above, unless the total string contains more than 200000 characters.