source: issm/trunk-jpl/src/py3/io/savevars.py@ 19895

import shelve
import os.path

def savevars(*args):
        """
        SAVEVARS - function to save variables to a file.

        This function saves one or more variables to a file.  The names of the variables
        must be supplied.  If more than one variable is specified, it may be done with
        lists of names and values or a dictionary of name:value pairs.  All the variables
        in the workspace may be saved by specifying the globals() dictionary, but this
        may include a lot of extraneous data.

        Usage:
           savevars('shelve.dat','a',a)
           savevars('shelve.dat',['a','b'],[a,b])
           savevars('shelve.dat',{'a':a,'b':b})
           savevars('shelve.dat',globals())

        """

        filename=''
        nvdict={}

        if len(args) >= 1 and isinstance(args[0],str):
                filename=args[0]
                if not filename:
                        filename='/tmp/shelve.dat'

        else:
                raise TypeError("Missing file name.")

        if   len(args) >= 3 and isinstance(args[1],str):    # (filename,name,value)
                for i in range(1,len(args),2):
                        nvdict[args[i]]=args[i+1]

        elif len(args) == 3 and isinstance(args[1],list) and isinstance(args[2],list):    # (filename,[names],[values])
                for name,value in zip(args[1],args[2]):
                        nvdict[name]=value

        elif len(args) == 2 and isinstance(args[1],dict):    # (filename,{names:values})
                nvdict=args[1]

        else:
                raise TypeError("Unrecognized input arguments.")

        if os.path.exists(filename):
                print("Shelving variables to existing file '%s'." % filename)
        else:
                print("Shelving variables to new file '%s'." % filename)

        my_shelf = shelve.open(filename,'c') # 'c' for create if not exist, else 'n' for new

        for name,value in nvdict.items():
                try:
                        my_shelf[name] = value
                        print("Variable '%s' shelved." % name)
                except TypeError:
                        print("Variable '%s' not shelved." % name)

        my_shelf.close()