Wildcard for range of numbers in ROOT

[FoxWise]

Hi, all

I have files named like:

1.root
2.root
...
999.root

I want to use a wildcard to load/analyze only first 42 of them.

In bash I would do something like this:
ls {0..42}.root

It seems I can’t do this in a code, as it results in error:
df = ROOT.RDataFrame("tree", "{0..42}.root")

Error in <TFile::TFile>: file /path/to/file/{0..42}.root does not exist

Is there workaround?

cheers,
Bohdan

[eguiraud]

RDF uses the same wildcard syntax as TChain, but I wouldn’t know how to do that with TChain (@pcanal ?).

A simple workaround it to use a list comprehension:

df = ROOT.RDataFrame("t", [str(n) + ".root" for n in range(1,43)])

Cheers,
Enrico

[yus]

Hi,

@eguiraud

I wouldn’t know how to do that with TChain

According to ROOT: TChain Class Reference ,

Wildcard treatment is triggered by any of the special characters []*? which may be used in the file name, e.g., specifying "xxx*.root" adds all files starting with xxx in the current file system directory.

[FoxWise]

Would it be possible to add {} symbols and their effects to the list of wildcard symbols?

[vpadulan]

Hi @FoxWise ,

I think you could try with the following

vpadulan@fedora [~/chaintest]: for i in {1..5}
> do
> touch file$i.root
> done
vpadulan@fedora [~/chaintest]: ls
file1.root  file2.root  file3.root  file4.root  file5.root
vpadulan@fedora [~/chaintest]: root
root [0] TChain c;
root [1] c.Add("file[1-3].root");
root [2] for (auto *el: *c.GetListOfFiles()) std::cout << el->GetTitle() << std::endl;
/home/vpadulan/chaintest/file1.root
/home/vpadulan/chaintest/file2.root
/home/vpadulan/chaintest/file3.root

Cheers,
Vincenzo

[FoxWise]

Hi, Vincenzo

[] doesn’t work with two digit numbers.
[0-42] is interpreted as [0-4,2]

cheers,
Bohdan