Class _process_plot_var_args

lib/matplotlib/axes/_base.py:241–554

Process variable length arguments to `~.Axes.plot`, to support :: plot(t, s) plot(t1, s1, t2, s2) plot(t1, s1, 'ko', t2, s2) plot(t1, s1, 'ko', t2, s2, 'r--', t3, e3) an arbitrary number of *x*, *y*, *fmt* are allowed

class _process_plot_var_args:
    """
    Process variable length arguments to `~.Axes.plot`, to support ::

      plot(t, s)
      plot(t1, s1, t2, s2)
      plot(t1, s1, 'ko', t2, s2)
      plot(t1, s1, 'ko', t2, s2, 'r--', t3, e3)

    an arbitrary number of *x*, *y*, *fmt* are allowed
    """

    def __init__(self, output='Line2D'):
        _api.check_in_list(['Line2D', 'Polygon', 'coordinates'], output=output)
        self.output = output
        self.set_prop_cycle(None)

    def set_prop_cycle(self, cycler):
        self._prop_cycle = _PropCycle(mpl._val_or_rc(cycler, 'axes.prop_cycle'))

    def __call__(self, axes, *args, data=None, return_kwargs=False, **kwargs):
        axes._process_unit_info(kwargs=kwargs)

        for pos_only in "xy":
            if pos_only in kwargs:
                raise _api.kwarg_error(inspect.stack()[1].function, pos_only)

        if not args:
            return

        if data is None:  # Process dict views
            args = [cbook.sanitize_sequence(a) for a in args]
        else:  # Process the 'data' kwarg.
            replaced = [mpl._replacer(data, arg) for arg in args]
            if len(args) == 1:
                label_namer_idx = 0
            elif len(args) == 2:  # Can be x, y or y, c.
                # Figure out what the second argument is.
                # 1) If the second argument cannot be a format shorthand, the
                #    second argument is the label_namer.
                # 2) Otherwise (it could have been a format shorthand),
                #    a) if we did perform a substitution, emit a warning, and
                #       use it as label_namer.
                #    b) otherwise, it is indeed a format shorthand; use the
                #       first argument as label_namer.
                try:
                    _process_plot_format(args[1])
                except ValueError:  # case 1)
                    label_namer_idx = 1
                else:
                    if replaced[1] is not args[1]:  # case 2a)
                        _api.warn_external(
                            f"Second argument {args[1]!r} is ambiguous: could "
                            f"be a format string but is in 'data'; using as "
                            f"data.  If it was intended as data, set the "
                            f"format string to an empty string to suppress "
                            f"this warning.  If it was intended as a format "
                            f"string, explicitly pass the x-values as well.  "