# [Julia 1.0], 20 bytes

<!-- language-all: lang-julia -->

    !s=join(i^2 for i=s)

[Try it online!][TIO-knk99kqq]

[Julia 1.0]: http://julialang.org/
[TIO-knk99kqq]: https://tio.run/##yyrNyUw0rPj/X7HYNis/M08jM85IIS2/SCHTtljzv0NxRn65gqKSEheMlZiUnJKalo4QcMkvTcpJVSguSE3MVoQL4xRHl/gPAA "Julia 1.0 – Try It Online"