Drawing Coordinates as Line in QGIS - PyQGIS

In this post I'll show some code for drawing a line from a list of coordinates, and saving it in a temporary vector layer.

You can implement the code below to get the coordinates from a text file, clipboard, or any user input.

Below are two functions that, called with the layer name and list of points as arguments, build a Line or Point temporary layer.

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def createLineLay(name,lstP):
    vl = QgsVectorLayer("Linestring", name, "memory")
    #pr = vl.dataProvider()
    vl.startEditing()
    vl.addAttribute(QgsField("id", QVariant.Int))
    vl.updateFields()
    fet = QgsFeature(vl.pendingFields())
    lstPP = []
    for p in lstP:
        lstPP.append(QgsPoint(float(p[0]),float(p[1])))
    lstPP.append(QgsPoint(float(lstP[0][0]),float(lstP[0][1])))
    fet.setGeometry(QgsGeometry.fromPolyline(lstPP))
    fields = vl.pendingFields()
    fet.setFields( fields, True )
    fet['id'] = 0
    pr = vl.dataProvider()
    pr.addFeatures( [ fet ] )
    vl.commitChanges()
    QgsMapLayerRegistry.instance().addMapLayer(vl)    

def createLayPts(name, lstP):
    vl = QgsVectorLayer("Point", name, "memory")
    #pr = vl.dataProvider()
    vl.startEditing()
    vl.addAttribute(QgsField("ID", QVariant.Int))
    vl.addAttribute(QgsField("X", QVariant.Double))
    vl.addAttribute(QgsField("Y", QVariant.Double))
    vl.updateFields()
    idP = 0
    for p in lstP:
        fet = QgsFeature(vl.pendingFields())
        fet.setGeometry(QgsGeometry.fromPoint(QgsPoint(float(p[0]),float(p[1]))))
        fields = vl.pendingFields()
        fet.setFields( fields, True )
        fet["ID"] = idP
        fet['X'] = p[0]
        fet['Y'] = p[1]
        pr = vl.dataProvider()
        pr.addFeatures( [ fet ] )
        vl.commitChanges()
        idP +=1
    QgsMapLayerRegistry.instance().addMapLayer(vl)