replace .format by f-strings if applicable

f-strings is faster, than `str().format`

Author: penguinolog

ipykernel/debugger.py

@@ -540,7 +540,7 @@ async def richInspectVariables(self, message):
         else:
             # The code has stopped on a breakpoint, we use the setExpression
             # request to get the rich representation of the variable
-            code = "get_ipython().display_formatter.format(" + var_name + ")"
+            code = f"get_ipython().display_formatter.format({var_name})"
             frame_id = message["arguments"]["frameId"]
             seq = message["seq"]
             reply = await self._forward_message(

ipykernel/iostream.py

@@ -253,9 +253,9 @@ def __getattr__(self, attr):
             super().__getattr__(attr)
         if hasattr(self.io_thread.socket, attr):
             warnings.warn(
-                "Accessing zmq Socket attribute {attr} on BackgroundSocket"
-                " is deprecated since ipykernel 4.3.0"
-                " use .io_thread.socket.{attr}".format(attr=attr),
+                f"Accessing zmq Socket attribute {attr} on BackgroundSocket"
+                f" is deprecated since ipykernel 4.3.0"
+                f" use .io_thread.socket.{attr}",
                 DeprecationWarning,
                 stacklevel=2,
             )
@@ -267,9 +267,9 @@ def __setattr__(self, attr, value):
             super().__setattr__(attr, value)
         else:
             warnings.warn(
-                "Setting zmq Socket attribute {attr} on BackgroundSocket"
-                " is deprecated since ipykernel 4.3.0"
-                " use .io_thread.socket.{attr}".format(attr=attr),
+                f"Setting zmq Socket attribute {attr} on BackgroundSocket"
+                f" is deprecated since ipykernel 4.3.0"
+                f" use .io_thread.socket.{attr}",
                 DeprecationWarning,
                 stacklevel=2,
             )

ipykernel/tests/test_async.py

@@ -54,7 +54,7 @@ def test_async_interrupt(asynclib, request):
 
     flush_channels(KC)
     msg_id = KC.execute(
-        "print('begin'); import {0}; await {0}.sleep(5)".format(asynclib)
+        f"print('begin'); import {asynclib}; await {asynclib}.sleep(5)"
     )
     busy = KC.get_iopub_msg(timeout=TIMEOUT)
     validate_message(busy, "status", msg_id)

ipykernel/tests/test_debugger.py

@@ -130,9 +130,9 @@ def test_set_breakpoints(kernel_with_debug):
 def test_rich_inspect_not_at_breakpoint(kernel_with_debug):
     var_name = "text"
     value = "Hello the world"
-    code = """{0}='{1}'
-print({0})
-""".format(var_name, value)
+    code = f"""{var_name}='{value}'
+print({var_name})
+"""
 
     msg_id = kernel_with_debug.execute(code)
     get_reply(kernel_with_debug, msg_id)

ipykernel/zmqshell.py

@@ -375,15 +375,14 @@ def connect_info(self, arg_s):
 
 
         print (info + '\n')
-        print ("Paste the above JSON into a file, and connect with:\n"
-            "    $> jupyter <app> --existing <file>\n"
-            "or, if you are local, you can connect with just:\n"
+        print (
+            f"Paste the above JSON into a file, and connect with:\n"
+            f"    $> jupyter <app> --existing <file>\n"
+            f"or, if you are local, you can connect with just:\n"
             f"    $> jupyter <app> --existing {connection_file}\n"
-            "or even just:\n"
-            "    $> jupyter <app> --existing\n"
-            "if this is the most recent Jupyter kernel you have started.".format(
-            connection_file
-            )
+            f"or even just:\n"
+            f"    $> jupyter <app> --existing\n"
+            f"if this is the most recent Jupyter kernel you have started."
         )
 
     @line_magic