CODEWITHSUNDEEP
stringmatlab
mortonjt
mortonjt

Reputation: 680

matlab string arrays

I have a list of files that I would like analyze. They are all named chr1.fa, chr2.fa, ... , chr22.fa, chrX.fa

I would like to store all of these filenames in an array. I know in python you can do

files = ["chr"+str(x)+".fa" for x in range(1,22)]+["chrX.fa"]

I have been having an embarrassingly difficult time trying to do the equivalent in Matlab. Otherwise, I'll have to initialize the file like:

files = {'chr1.fa','chr2.fa',...,'chr22.fa','chrX.fa'}

Which is really not ideal since I may be processing more files.

Any pointers on where I should be looking would be greatly appreciated.

Thanks!

Upvotes: 3

Views: 1903

Answers (5)

matlabbit
matlabbit

Reputation: 706

Old topic, but starting in 16b, using the new string datatype makes this pretty easy:

>> files = ["chr" + (1:22) + ".fa", "chrX.fa"]'

files = 

  23×1 string array

    "chr1.fa"
    "chr2.fa"
    "chr3.fa"
    "chr4.fa"
    "chr5.fa"
    "chr6.fa"
    "chr7.fa"
    "chr8.fa"
    "chr9.fa"
    "chr10.fa"
    "chr11.fa"
    "chr12.fa"
    "chr13.fa"
    "chr14.fa"
    "chr15.fa"
    "chr16.fa"
    "chr17.fa"
    "chr18.fa"
    "chr19.fa"
    "chr20.fa"
    "chr21.fa"
    "chr22.fa"
    "chrX.fa"

Upvotes: 0

Amro
Amro

Reputation: 124563

Try:

files = [strtrim(cellstr(num2str((1:22)','chr%d.fa'))) ; 'chrX.fa']

Upvotes: 1

Jonas
Jonas

Reputation: 74940

Here's a more concise version using sprintf and strsplit:

files = strsplit(sprintf('chr%i.fa ',1:22),' ');

files{end} = 'chrX.fa';

Upvotes: 3

tmpearce
tmpearce

Reputation: 12693

Here's a one-liner, just for fun. @Phonon's way works too obviously.

 files = [arrayfun(@(x)strcat('chr',num2str(x),'.fa'),(1:22)','uni',0); 'chrX.fa']

Upvotes: 2

Phonon
Phonon

Reputation: 12737

This isn't exactly as compact as Python, but it'll do the job for you.

N = 20;

prefix = 'chr';
suffix = '.fa';

names = cell(N,1);

for n = 1:N
    names{n} = [prefix int2str(n) suffix];
end

names{N+1} = [prefix 'X' suffix];

You can fetch names by names{index}. Note the curly braces, since this is a cell array, not a multidimensional character array.

Upvotes: 3

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