add new api for labels

Author: alexpvpmindustry

src/mplfinance/_arg_validators.py

@@ -95,17 +95,18 @@ def _check_and_prepare_data(data, config):
     return dates, opens, highs, lows, closes, volumes
 
 def _label_validator(label_value):
-    ''' Validates the input of labels for the added plots.
+    ''' Validates the input of label for the added plots.
     label_value may be a str or a list of str.
     '''
     if isinstance(label_value,str):
         return True
-    elif not isinstance(label_value,(tuple,list)):
-        return False
-    for label in label_value:
-        if not isinstance(label,str):
-            return False
-    return True
+    return False
+    # elif not isinstance(label_value,(tuple,list)):
+    #     return False
+    # for label in label_value:
+    #     if not isinstance(label,str):
+    #         return False
+    # return True
 
 def _get_valid_plot_types(plottype=None):
 

src/mplfinance/plotting.py

@@ -752,6 +752,8 @@ def plot( data, **kwargs ):
 
         elif not _list_of_dict(addplot):
             raise TypeError('addplot must be `dict`, or `list of dict`, NOT '+str(type(addplot)))
+        
+        contains_legend_label=[] # a list of axes that contains legend labels
 
         for apdict in addplot:
 
@@ -779,6 +781,10 @@ def plot( data, **kwargs ):
                     ydata = apdata.loc[:,column] if havedf else column
                     ax = _addplot_columns(panid,panels,ydata,apdict,xdates,config)
                     _addplot_apply_supplements(ax,apdict,xdates)
+                if apdict["label"]: # not supported for aptype == 'ohlc' or 'candle'
+                    contains_legend_label.append(ax)
+        for ax in set(contains_legend_label): # there will be duplicates, 
+            ax.legend() # but its ok to call ax.legend() multiple times
 
     # fill_between is NOT supported for external_axes_mode
     # (caller can easily call ax.fill_between() themselves).
@@ -1088,46 +1094,38 @@ def _addplot_columns(panid,panels,ydata,apdict,xdates,config):
         ax = apdict['ax']
 
     aptype = apdict['type']
+    label = apdict['label']
     if aptype == 'scatter':
         size  = apdict['markersize']
         mark  = apdict['marker']
         color = apdict['color']
         alpha = apdict['alpha']
-        labels = apdict['labels']
         edgecolors  = apdict['edgecolors']
         linewidths = apdict['linewidths']
 
         if isinstance(mark,(list,tuple,np.ndarray)):
             _mscatter(xdates, ydata, ax=ax, m=mark, s=size, color=color, alpha=alpha, edgecolors=edgecolors, linewidths=linewidths)
-        else:
-            ax.scatter(xdates, ydata, s=size, marker=mark, color=color, alpha=alpha, edgecolors=edgecolors, linewidths=linewidths)
-            if labels is not None:
-                ax.legend(labels=labels)
+        else: 
+            ax.scatter(xdates, ydata, s=size, marker=mark, color=color, alpha=alpha, edgecolors=edgecolors, linewidths=linewidths,label=label) 
     elif aptype == 'bar':
         width  = 0.8 if apdict['width'] is None else apdict['width']
         bottom = apdict['bottom']
         color  = apdict['color']
         alpha  = apdict['alpha']
-        ax.bar(xdates,ydata,width=width,bottom=bottom,color=color,alpha=alpha)
-        if apdict['labels'] is not None:
-            ax.legend(labels=apdict['labels'])
+        ax.bar(xdates,ydata,width=width,bottom=bottom,color=color,alpha=alpha,label=label)
     elif aptype == 'line':
         ls     = apdict['linestyle']
         color  = apdict['color']
         width  = apdict['width'] if apdict['width'] is not None else 1.6*config['_width_config']['line_width']
         alpha  = apdict['alpha']
-        ax.plot(xdates,ydata,linestyle=ls,color=color,linewidth=width,alpha=alpha)
-        if apdict['labels'] is not None:
-            ax.legend(labels=apdict['labels'])
+        ax.plot(xdates,ydata,linestyle=ls,color=color,linewidth=width,alpha=alpha,label=label)
     elif aptype == 'step':
         stepwhere = apdict['stepwhere']
         ls = apdict['linestyle']
         color  = apdict['color']
         width  = apdict['width'] if apdict['width'] is not None else 1.6*config['_width_config']['line_width']
         alpha  = apdict['alpha']
-        ax.step(xdates,ydata,where = stepwhere,linestyle=ls,color=color,linewidth=width,alpha=alpha)
-        if apdict['labels'] is not None:
-            ax.legend(labels=apdict['labels'])
+        ax.step(xdates,ydata,where = stepwhere,linestyle=ls,color=color,linewidth=width,alpha=alpha,label=label)
     else:
         raise ValueError('addplot type "'+str(aptype)+'" NOT yet supported.')
 
@@ -1380,8 +1378,8 @@ def _valid_addplot_kwargs():
         'fill_between': { 'Default'     : None,    # added by Wen
                           'Description' : " fill region",
                           'Validator'   : _fill_between_validator },
-        "labels"      : { 'Default'     : None,
-                          'Description' : 'Labels for the added plot.',
+        "label"      : { 'Default'     : None,
+                          'Description' : 'Label for the added plot. One per added plot.',
                           'Validator'   : _label_validator },
 
     }