Module r_util

Expand environment variable in a file name.

If the input file name begins with either a Unix-style or IRAF-style environment variable (e.g. $lref/name_dqi.fits or lref$name_dqi.fits respectively), this routine expands the variable and returns a complete path name for the file.

Parameters:

• filename (string) - a file name, possibly including an environment variable

Returns: string

the file name with environment variable expanded

Interpolate.

Linear interpolation is used. If the specified indpendent variable value xp is outside the range of the array x, the first (or last) value in values will be returned.

Parameters:

• x (a sequence object, e.g. an array, int or float) - array of independent variable values
• values (a sequence object, e.g. an array (not character)) - array of dependent variable values
• xp (int or float) - independent variable value at which to interpolate

Returns: the same type as one element of values

linearly interpolated value