Use str.removeprefix()/removesuffix()

These functions are now available in all supported Python versions.

Author: victorlin

nextstrain/cli/command/shell.py

@@ -10,7 +10,7 @@
 from ..argparse import add_extended_help_flags
 from ..paths import SHELL_HISTORY
 from ..runner import docker, conda, singularity
-from ..util import colored, remove_prefix, runner_name
+from ..util import colored, runner_name
 from ..volume import NamedVolume
 from .build import assert_overlay_volumes_support, pathogen_volumes
 
@@ -113,7 +113,7 @@ def fg(color: str) -> str: return r'\[\e[38;2;{};{};{}m\]'.format(*rgb(color))
     def bg(color: str) -> str: return r'\[\e[48;2;{};{};{}m\]'.format(*rgb(color))
 
     def rgb(color: str) -> Tuple[int, int, int]:
-        color = remove_prefix("#", color)
+        color = color.removeprefix("#")
         r,g,b = (int(c, 16) for c in (color[0:2], color[2:4], color[4:6]))
         return r,g,b
 

nextstrain/cli/command/view.py

@@ -59,7 +59,7 @@
 from ..argparse import add_extended_help_flags, SUPPRESS, SKIP_AUTO_DEFAULT_IN_HELP
 from ..browser import BROWSER, open_browser as __open_browser
 from ..runner import docker, ambient, conda, singularity
-from ..util import colored, remove_suffix, warn
+from ..util import colored, warn
 from ..volume import NamedVolume
 
 
@@ -324,7 +324,7 @@ def sidecar_file(path):
 
     # v1: All *_tree.json files with corresponding *_meta.json files.
     def meta_exists(path):
-        return path.with_name(remove_suffix("_tree.json", path.name) + "_meta.json").exists()
+        return path.with_name(path.name.removesuffix("_tree.json") + "_meta.json").exists()
 
     datasets_v1 = set(
         re.sub(r"_tree$", "", path.stem).replace("_", "/")

nextstrain/cli/remote/nextstrain_dot_org.py

@@ -86,7 +86,7 @@
 from ..gzip import GzipCompressingReader
 from ..net import is_loopback
 from ..url import URL, Origin
-from ..util import remove_prefix, glob_matcher, glob_match
+from ..util import glob_matcher, glob_match
 
 
 # Default to embedding images, but allow it to be turned off as an escape
@@ -971,7 +971,7 @@ def authn_challenge(response: requests.Response) -> Optional[Dict[str, str]]:
     if not challenge or not challenge.startswith("Bearer "):
         return None
 
-    challenge_params = remove_prefix("Bearer ", challenge).lstrip(" ")
+    challenge_params = challenge.removeprefix("Bearer ").lstrip(" ")
 
     return requests.utils.parse_dict_header(challenge_params)
 

nextstrain/cli/remote/s3.py

@@ -51,7 +51,7 @@
 from ..aws.s3 import split_url
 from ..authn import User
 from ..gzip import GzipCompressingReader, ContentDecodingWriter
-from ..util import warn, remove_prefix
+from ..util import warn
 from ..errors import UserError
 from ..types import S3Object
 from ..url import URL, Origin
@@ -454,4 +454,4 @@ def remove_origin_path(origin: dict, prefix: str) -> str:
     """
     Return the given prefix stripped of any implicit distribution origin path.
     """
-    return remove_prefix(origin["OriginPath"].lstrip("/"), prefix)
+    return prefix.removeprefix(origin["OriginPath"].lstrip("/"))

nextstrain/cli/rst/__init__.py

@@ -24,7 +24,6 @@
 from docutils.parsers.rst.roles import register_local_role
 from docutils.utils import unescape
 from ..__version__ import __version__ as cli_version
-from ..util import remove_suffix
 from .sphinx import TextWriter
 
 
@@ -225,7 +224,7 @@ def doc_url(target: str) -> str:
 
     if path.endswith("/index"):
         # a/b/index → a/b/ (e.g. implicitly a/b/index.html)
-        path_url = remove_suffix("index", path)
+        path_url = path.removesuffix("index")
     else:
         path_url = path + (suffix or "")
 

nextstrain/cli/util.py

@@ -64,14 +64,6 @@ def colored(color, text):
     )
 
 
-# TODO: Use str.removeprefix/removesuffix once Python 3.9 is the minimum supported version.
-def remove_prefix(prefix, string):
-    return re.sub('^' + re.escape(prefix), '', string)
-
-def remove_suffix(suffix, string):
-    return re.sub(re.escape(suffix) + '$', '', string)
-
-
 class NewVersionCheckResult(NamedTuple):
     newer_version: Optional[str]
     status_message: Optional[str]
@@ -724,7 +716,7 @@ def print_and_check_setup_tests(tests: SetupTestResults) -> bool:
         # Indent subsequent lines of any multi-line descriptions so it
         # lines up under the status marker.
         formatted_description = \
-            remove_prefix("  ", indent(description, "  "))
+            indent(description, "  ").removeprefix("  ")
 
         results.append((description, result))