The concept of a list comprehenshion is sinple but syntax is awful, as if Yoda was writing a for loop. "x for x in y it is, hmm yes".

I'm not saying I don't understand them. I'm saying the syntax is terrible. Compare it to Ruby (or any other modern language) and it's abundantly clear.

python (uses syntax not available in any other top 25 language)

print([j**2 for j in [2, 3, 4, 5]]) # => [4, 9, 16, 25]

ruby (normal chain syntax with map)

puts [2, 3, 4, 5].map{|j| j**2}

even kotlin is more readable, even though you have to convert to a double and back kotlin

val list = listOf(1,2,3,4)
println(list.map{it.toDouble().pow(2.0).toInt()})

For nested cases it's even more apparent:

python

digits = [1, 2, 3]
chars = ['a', 'b', 'c']    
print([str(d)+ch for d in digits for ch in chars if d >= 2 if ch == 'a'])    
# => ['2a', '3a']

ruby

digits = [1, 2, 3]
chars = ['a', 'b', 'c']   
digits.product(chars).select{ |d, ch| d >= 2 && ch == 'a' }.map(&:join)

kotlin

val digits = listOf(1, 2, 3)
val chars = listOf('a', 'b', 'c')
println(digits.flatMap { d ->
    chars.filter { ch -> d >= 2 && ch == 'a' }.map { ch -> "${d}${ch}" }})

just from a base level, you have to read the middle of the comprehension first, then the end, then the beginning. It's a completely backwards way to write and read code. unlike other languages that use a 'functional' approach, where it's chained methods or pipes, etc. Even Elixir, which does have list comprehensions, reads and writes in the proper order:

elixir

for x <- 0..100, x * x > 3, do: x * 2