I would do it this way:
julia> a
"GAMG: Solving for p, Initial residual = 1, Final residual = 0.0580078, No Iterations 7"
julia> m = match(r".*Initial residual =\s(.*),.*Final residual =\s(.*),", a);
julia> parse.(Float64, m.captures)
2-element Vector{Float64}:
1.0
0.0580078
guess work:
const f = eachline("Cruciform/Post-Processing/hellothere.txt")
let storage = Float64[]
for l in f
if occursin("Solving for p", l)
m = match(r".*Initial residual =\s(.*),.*Final residual =\s(.*),", l)
init, final = parse.(Float64, m.captures)
push!(storage, init)
end
end
display(storage)
end