El lunes, 6 de octubre de 2014 11:56:36 UTC-5, David P. Sanders escribió: > > > > El lunes, 6 de octubre de 2014 03:01:07 UTC-5, JVaz escribió: >> >> Hello, I am new in Julia and it's the first time I publish here, but I >> actually would find it useful to modify a string. For example, I want to do: >> >> > string = "ACTGACTG" >> string[3] = A --> (error) >> > It turns out that there is in fact already a package to work with biological sequences:
https://github.com/diegozea/BioSeq.jl David. > > There is no particular reason to treat the sequence as a string; it's just > a collection of symbols. > So an option is to replace it with an array of characters: > > julia> sequence = "ACTGACTG" > "ACTGACTG" > > julia> bases = [c for c in sequence] > 8-element Array{Any,1}: > 'A' > 'C' > 'T' > 'G' > 'A' > 'C' > 'T' > 'G' > > julia> > > julia> bases[3] = 'A' > 'A' > > julia> bases' > 1x8 Array{Any,2}: > 'A' 'C' 'A' 'G' 'A' 'C' 'T' 'G' > > (I put ' after bases just to save space in the output; it takes the > transpose of the array.) > > Note that since the entries of the array 'bases' are now characters, they > must be written with apostrophes / quotes instead of double quotes. > Also note that the code is more legible since there are readable and > understandable names for the variables. > > The definition of bases uses an 'array comprehension'. > > > To get a bit more abstract, you could instead make an array of symbols: > > julia> sequence = "ACTGACTG" > "ACTGACTG" > > julia> bases = [symbol(c) for c in sequence]; > > julia> > > julia> bases[3] = :A > :A > > julia> bases' > 1x8 Array{Any,2}: > :A :C :A :G :A :C :T :G > > so that you really have abstract symbols, instead of characters. > (:A means "the symbol with the name 'A' in Julia; see, for example, my > tutorial) > > The semicolon suppresses output. > > > >> >> And I cannot use replace because I don't wanna change all the T, I just >> wanna change the third character in the string. >> For me, it is useful that they are trings because then "after a mutation" >> I can easily check if two strings are the same, e.g: >> >> How could I do that, then? >> Thanks >> >
