clean-up in gui/qt/main_window.py: use string.format for translated strings, and some indentation

gui/qt/main_window.py

@@ -553,24 +553,24 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
             return
         self.print_error("Notifying GUI")
         if len(self.tx_notifications) > 0:
-            # Combine the transactions if there are more then three
-            tx_amount = len(self.tx_notifications)
-            if(tx_amount >= 3):
+            # Combine the transactions if there are at least three
+            num_txns = len(self.tx_notifications)
+            if num_txns >= 3:
                 total_amount = 0
                 for tx in self.tx_notifications:
                     is_relevant, is_mine, v, fee = self.wallet.get_wallet_delta(tx)
-                    if(v > 0):
+                    if v > 0:
                         total_amount += v
-                self.notify(_("%(txs)s new transactions received: Total amount received in the new transactions %(amount)s") \
-                            % { 'txs' : tx_amount, 'amount' : self.format_amount_and_units(total_amount)})
+                self.notify(_("{} new transactions received: Total amount received in the new transactions {}")
+                            .format(num_txns, self.format_amount_and_units(total_amount)))
                 self.tx_notifications = []
             else:
-              for tx in self.tx_notifications:
-                  if tx:
-                      self.tx_notifications.remove(tx)
-                      is_relevant, is_mine, v, fee = self.wallet.get_wallet_delta(tx)
-                      if(v > 0):
-                          self.notify(_("New transaction received: %(amount)s") % { 'amount' : self.format_amount_and_units(v)})
+                for tx in self.tx_notifications:
+                    if tx:
+                        self.tx_notifications.remove(tx)
+                        is_relevant, is_mine, v, fee = self.wallet.get_wallet_delta(tx)
+                        if v > 0:
+                            self.notify(_("New transaction received: {}").format(self.format_amount_and_units(v)))
 
     def notify(self, message):
         if self.tray:
@@ -698,7 +698,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
                 text = _("Synchronizing...")
                 icon = QIcon(":icons/status_waiting.png")
             elif server_lag > 1:
-                text = _("Server is lagging (%d blocks)"%server_lag)
+                text = _("Server is lagging ({} blocks)").format(server_lag)
                 icon = QIcon(":icons/status_lagging.png")
             else:
                 c, u, x = self.wallet.get_balance()
@@ -1425,7 +1425,8 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
 
             if self.payto_e.is_alias and self.payto_e.validated is False:
                 alias = self.payto_e.toPlainText()
-                msg = _('WARNING: the alias "%s" could not be validated via an additional security check, DNSSEC, and thus may not be correct.'%alias) + '\n'
+                msg = _('WARNING: the alias "{}" could not be validated via an additional '
+                        'security check, DNSSEC, and thus may not be correct.').format(alias) + '\n'
                 msg += _('Do you wish to continue?')
                 if not self.question(msg):
                     return
@@ -1788,8 +1789,8 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         return True
 
     def delete_contacts(self, labels):
-        if not self.question(_("Remove %s from your list of contacts?")
-                             % " + ".join(labels)):
+        if not self.question(_("Remove {} from your list of contacts?")
+                             .format(" + ".join(labels))):
             return
         for label in labels:
             self.contacts.pop(label)