ngect.utils module

ngect.utils.check_dir(filename)

Ensure the parent directory of a file path exists.

Parameters

filename : str

The file path whose parent directory should be checked/created.

Returns

bool

True if the directory already existed, False if it was created by this call.

Notes

This helper does not create the file itself; it only ensures that the directory component of filename exists. If filename has no directory component (e.g., "file.txt"), this function returns True and performs no action.

ngect.utils.get_si_prefix(value: float, select: str = 'mu', lztol: int = 0) → tuple

Choose a readable SI prefix for a numeric value.

Determines the prefix that minimizes leading zeros (within a tolerance) and keeps a small number of digits before the decimal point after scaling the value.

Parameters

valuefloat

The numeric value to scale.

selectstr, optional

String containing the set of candidate SI prefixes to consider. Must be a subset of "yzafpnum kMGTPEZY" (a space represents no prefix). Defaults to "mu" (micro and none).

lztolint, optional

Leading-zero tolerance used when selecting the prefix. Higher values allow more leading zeros before switching to a smaller unit. Default is 0.

Returns

tuple

(prefix: str, scale: float) where prefix is the chosen SI prefix symbol (e.g., "m", "u", "k", or "" for none) and scale is the multiplicative factor corresponding to that prefix (e.g., 1e-3 for "m", 1e6 for "M").

Notes

The full ordered table of supported prefixes is:

"yzafpnum kMGTPEZY"

The space character denotes the base unit (no prefix).

Examples

Frequency value in Hz:

>>> get_si_prefix(10**7, select='kMGT')
('M', 1000000.0)

Flux value in Jy:

>>> get_si_prefix(1.0, select='um')
('', 1.0)
>>> get_si_prefix(0.0, select='um')
('', 1.0)
>>> get_si_prefix(-0.9, select='um')
('m', 0.001)
>>> get_si_prefix(0.9, select='um', lztol=1)
('', 1.0)
>>> get_si_prefix(1e-7, select='um')
('u', 1e-06)
>>> get_si_prefix(1e3, select='um')
('', 1.0)