Replace key existence tests with dict.get()

Replaced instances of this pattern:

if 'key' in somedict:
    var = somedict['key']
else:
    var = ""

...with this much simpler pattern:

var = somedict.get('key', "")

Some variations, like returning None if the key is not found were also
replaced.

zenmap/radialnet/core/XMLHandler.py

@@ -179,10 +179,7 @@ class XMLNode:
     def get_attr(self, attr):
         """
         """
-        if attr in self.__attrs:
-            return self.__attrs[attr]
-
-        return None
+        return self.__attrs.get(attr)
 
     def get_attrs(self):
         """

zenmap/radialnet/gui/NodeNotebook.py

@@ -254,17 +254,9 @@ class ServicesPage(gtk.Notebook):
 
             color = get_service_color(port['state']['state'])
 
-            if 'name' in port['service']:
-                service_name = port['service']['name']
+            service_name = port['service'].get('name', _('<unknown>'))
 
-            else:
-                service_name = _('<unknown>')
-
-            if 'method' in port['service']:
-                service_method = port['service']['method']
-
-            else:
-                service_method = _('<none>')
+            service_method = port['service'].get('method', _('<none>'))
 
             reference = self.__ports_store.append(None,
                                                   [port['id'],
@@ -576,10 +568,7 @@ class SystemPage(BWScrolledWindow):
 
                 for os_class in os['classes']:
 
-                    os_gen = ''
-
-                    if 'os_gen' in os_class:
-                        os_gen = os_class['os_gen']
+                    os_gen = os_class.get('os_gen', '')
 
                     self.__class_store.append([os_class['accuracy'],
                                                os_class['vendor'],

zenmap/radialnet/gui/RadialNet.py

@@ -2042,10 +2042,7 @@ class NetNode(Node):
         if info == None:
             return self.__draw_info
 
-        if info in self.__draw_info:
-            return self.__draw_info[info]
-
-        return None
+        return self.__draw_info.get(info)
 
     def set_draw_info(self, info):
         """

zenmap/zenmapGUI/DiffCompare.py

@@ -293,18 +293,12 @@ class ScanChooser(HIGVBox):
         """Return the currently selected scan's parsed output as an NmapParser
         object, or None if no valid scan is selected."""
         selected_scan = self.combo_scan.child.get_text()
-        if selected_scan in self.scan_dict:
-            return self.scan_dict[selected_scan]
-        # What's typed in the entry doesn't match a registered scan.
-        return None
+        return self.scan_dict.get(selected_scan)
 
     def get_nmap_output(self):
         """Return the currently selected scan's output as a string, or None if
         no valid scan is selected."""
-        parsed = self.parsed_scan
-        if parsed is not None:
-            return parsed.nmap_output
-        return None
+        return self.parsed_scan
 
     nmap_output = property(get_nmap_output)
     parsed_scan = property(get_parsed_scan)

zenmap/zenmapGUI/ProfileHelp.py

@@ -137,28 +137,19 @@ class ProfileHelp:
         self.labels[option_name] = text
 
     def get_label(self):
-        if self.currentstate in self.labels.keys():
-            return self.labels[self.currentstate]
-        else:
-            return ""  # blank
+        return self.labels.get(self.currentstate, "")
 
     def add_shortdesc(self, option_name, text):
         self.descs[option_name] = text
 
     def get_shortdesc(self):
-        if self.currentstate in self.descs.keys():
-            return self.descs[self.currentstate]
-        else:
-            return ""  # blank
+        return self.descs.get(self.currentstate, "")
 
     def add_example(self, option_name, text):
         self.examples[option_name] = text
 
     def get_example(self):
-        if self.currentstate in self.examples.keys():
-            return self.examples[self.currentstate]
-        else:
-            return ""  # blank
+        return self.examples.get(self.currentstate, "")
 
     def handler(self, whichLabel):
         log.debug("whichLabel: %s" % whichLabel)