ENH: add str.removeprefix

doc/source/whatsnew/v1.3.0.rst

@@ -53,6 +53,7 @@ Other enhancements
 - :meth:`DataFrame.apply` can now accept non-callable DataFrame properties as strings, e.g. ``df.apply("size")``, which was already the case for :meth:`Series.apply` (:issue:`39116`)
 - :meth:`Series.apply` can now accept list-like or dictionary-like arguments that aren't lists or dictionaries, e.g. ``ser.apply(np.array(["sum", "mean"]))``, which was already the case for :meth:`DataFrame.apply` (:issue:`39140`)
 - :meth:`.Styler.set_tooltips` allows on hover tooltips to be added to styled HTML dataframes.
+- Added :meth:`Series.str.removeprefix` to remove prefixes from string type Series, which has the same functionality as ``str.removeprefix`` from the Python standard library.
 
 .. ---------------------------------------------------------------------------
 

pandas/core/strings/accessor.py

@@ -2885,6 +2885,14 @@ def casefold(self):
         "isdecimal", docstring=_shared_docs["ismethods"] % _doc_args["isdecimal"]
     )
 
+    @forbid_nonstring_types(["bytes"])
+    def removeprefix(self, prefix=None):
+        if not prefix:
+            return self._data
+        else:
+            result = self._data.array._str_removeprefix(prefix)
+            return self._wrap_result(result)
+
 
 def cat_safe(list_of_columns: List, sep: str):
     """

pandas/core/strings/base.py

@@ -223,3 +223,7 @@ def _str_split(self, pat=None, n=-1, expand=False):
     @abc.abstractmethod
     def _str_rsplit(self, pat=None, n=-1):
         pass
+
+    @abc.abstractmethod
+    def _str_removeprefix(self, prefix=None):
+        pass

pandas/core/strings/object_array.py

@@ -430,3 +430,6 @@ def _str_lstrip(self, to_strip=None):
 
     def _str_rstrip(self, to_strip=None):
         return self._str_map(lambda x: x.rstrip(to_strip))
+
+    def _str_removeprefix(self, prefix=None):
+        return self._str_map(lambda x: x.removeprefix(prefix))

pandas/tests/test_strings.py

@@ -1,5 +1,6 @@
 from datetime import datetime, timedelta
 import re
+import sys
 
 import numpy as np
 import pytest
@@ -65,6 +66,7 @@ def assert_series_or_index_equal(left, right):
     ("translate", ({97: 100},), {}),
     ("wrap", (2,), {}),
     ("zfill", (10,), {}),
+    ("removeprefix", ("a ",), {}),
 ] + list(
     zip(
         [
@@ -307,8 +309,18 @@ def test_api_for_categorical(self, any_string_method):
 
         method_name, args, kwargs = any_string_method
 
-        result = getattr(c.str, method_name)(*args, **kwargs)
-        expected = getattr(s.str, method_name)(*args, **kwargs)
+        # we expect an AttributeError when str.removeprefix is tested on <= 3.9
+        if (
+            sys.version_info[0] <= 3
+            and sys.version_info[1] < 9
+            and method_name == "removeprefix"
+        ):
+            with pytest.raises(AttributeError):
+                result = getattr(c.str, method_name)(*args, **kwargs)
+                expected = getattr(s.str, method_name)(*args, **kwargs)
+        else:
+            result = getattr(c.str, method_name)(*args, **kwargs)
+            expected = getattr(s.str, method_name)(*args, **kwargs)
 
         if isinstance(result, DataFrame):
             tm.assert_frame_equal(result, expected)
@@ -3678,3 +3690,17 @@ def test_str_accessor_in_apply_func():
     expected = Series(["A/D", "B/E", "C/F"])
     result = df.apply(lambda f: "/".join(f.str.upper()), axis=1)
     tm.assert_series_equal(result, expected)
+
+
+@pytest.mark.skipif(
+    sys.version_info[0] <= 3 and sys.version_info[1] < 9,
+    reason="Requires python 3.9 or greater",
+)
+def test_str_removeprefix():
+    # https://github.com/pandas-dev/pandas/issues/36944
+
+    df = DataFrame({"A": ["str_string1", "str_string2", "str_string3"]})
+    df["A"] = df["A"].str.removeprefix("str_")
+    result = DataFrame({"A": ["string1", "string2", "string3"]})
+
+    tm.assert_frame_equal(df, result)