Several utility functions are used throughout sisl.

Range routines

strmap(func, s[, start, end, sep])	Parse a string as though it was a slice and map all entries using func.
strseq(cast, s[, start, end])	Accept a string and return the casted tuples of content based on ranges.
lstranges(lst[, cast, end])	Convert a strmap list into expanded ranges
erange(start, step[, end])	Returns the range with both ends includede
list2str(lst)	Convert a list of elements into a string of ranges
fileindex(f[, cast])	Parses a filename string into the filename and the indices.

Miscellaneous routines

str_spec(name)	Split into a tuple of name and specifier, delimited by {...}.
direction(d[, abc, xyz])	Index coordinate transformation from int/str to an integer
listify	Convert arguments to an iterable-like (any iterable, default to list)
angle(s[, rad, in_rad])	Convert the input string to an angle, either radians or degrees.
iter_shape(shape)	Generator for iterating a shape by returning consecutive slices
math_eval(expr)	Evaluate a mathematical expression using a safe evaluation method
batched_indices(ref, y[, axis, atol, ...])	Locate x in ref by examining np.abs(diff_func(ref - y)) <= atol