numpy · mattip · Jun 4, 2019 · Feb 1, 2019 · Feb 4, 2019 · Feb 5, 2019
diff --git a/doc/release/1.17.0-notes.rst b/doc/release/1.17.0-notes.rst
@@ -328,6 +328,11 @@ concatenation.
 In some cases where ``np.interp`` would previously return ``np.nan``, it now
 returns an appropriate infinity.
 
+Pathlib support for ``np.fromfile``, ``ndarray.tofile`` and ``ndarray.dump``
+----------------------------------------------------------------------------
+``np.fromfile``, ``np.ndarray.tofile`` and ``np.ndarray.dump`` now support
+the `pathlib.Path` type for the ``file``/``fid`` parameter.
+
 Specialized ``np.isnan``, ``np.isinf``, and ``np.isfinite`` ufuncs for bool and int types
 -----------------------------------------------------------------------------------------
 The boolean and integer types are incapable of storing ``np.nan`` and

diff --git a/numpy/core/_add_newdocs.py b/numpy/core/_add_newdocs.py
@@ -1152,8 +1152,12 @@
 
     Parameters
     ----------
-    file : file or str
+    file : file or str or Path
         Open file object or filename.
+
+        .. versionchanged:: 1.17.0
+            `pathlib.Path` objects are now accepted.
+
     dtype : data-type
         Data type of the returned array.
         For binary files, it is used to determine the size and byte-order
@@ -2962,9 +2966,12 @@
 
     Parameters
     ----------
-    file : str
+    file : str or Path
         A string naming the dump file.
 
+        .. versionchanged:: 1.17.0
+            `pathlib.Path` objects are now accepted.
+
     """))
 
 
@@ -4009,8 +4016,12 @@
 
     Parameters
     ----------
-    fid : file or str
+    fid : file or str or Path
         An open file object, or a string containing a filename.
+
+        .. versionchanged:: 1.17.0
+            `pathlib.Path` objects are now accepted.
+
     sep : str
         Separator between array items for text output.
         If "" (empty), a binary file is written, equivalent to

diff --git a/numpy/core/src/multiarray/methods.c b/numpy/core/src/multiarray/methods.c
@@ -577,6 +577,10 @@ array_tofile(PyArrayObject *self, PyObject *args, PyObject *kwds)
         return NULL;
     }
 
+    file = NpyPath_PathlikeToFspath(file);
+    if (file == NULL) {
+        return NULL;
+    }
     if (PyBytes_Check(file) || PyUnicode_Check(file)) {
         file = npy_PyFile_OpenFile(file, "wb");
         if (file == NULL) {

diff --git a/numpy/core/src/multiarray/methods.h b/numpy/core/src/multiarray/methods.h
@@ -1,9 +1,32 @@
 #ifndef _NPY_ARRAY_METHODS_H_
 #define _NPY_ARRAY_METHODS_H_
 
+#include "npy_import.h"
+
 extern NPY_NO_EXPORT PyMethodDef array_methods[];
 
 NPY_NO_EXPORT const char *
 npy_casting_to_string(NPY_CASTING casting);
 
+/* Pathlib support */
+static inline PyObject *
+NpyPath_PathlikeToFspath(PyObject *file)
+{
+    static PyObject *os_PathLike = NULL;
+    static PyObject *os_fspath = NULL;
+    npy_cache_import("numpy.compat", "os_PathLike", &os_PathLike);
+    if (os_PathLike == NULL) {
+        return NULL;
+    }
+    npy_cache_import("numpy.compat", "os_fspath", &os_fspath);
+    if (os_fspath == NULL) {
+        return NULL;
+    }
+
+    if (!PyObject_IsInstance(file, os_PathLike)) {
+        return file;
+    }
+    return PyObject_CallFunctionObjArgs(os_fspath, file, NULL);
+}
+
 #endif
diff --git a/numpy/core/src/multiarray/multiarraymodule.c b/numpy/core/src/multiarray/multiarraymodule.c
@@ -2078,6 +2078,12 @@ array_fromfile(PyObject *NPY_UNUSED(ignored), PyObject *args, PyObject *keywds)
         Py_XDECREF(type);
         return NULL;
     }
+
+    file = NpyPath_PathlikeToFspath(file);
+    if (file == NULL) {
+        return NULL;
+    }
+
     if (offset != 0 && strcmp(sep, "") != 0) {
         PyErr_SetString(PyExc_TypeError, "'offset' argument only permitted for binary files");
         return NULL;

diff --git a/numpy/core/tests/test_multiarray.py b/numpy/core/tests/test_multiarray.py
@@ -23,6 +23,14 @@
 
 from numpy.compat import pickle
 
+try:
+    import pathlib
+except ImportError:
+    try:
+        import pathlib2 as pathlib
+    except ImportError:
+        pathlib = None
+
 if sys.version_info[0] >= 3:
     import builtins
 else:
@@ -4639,6 +4647,20 @@ def test_roundtrip_filename(self):
         y = np.fromfile(self.filename, dtype=self.dtype)
         assert_array_equal(y, self.x.flat)
 
+    @pytest.mark.skipif(pathlib is None, reason="pathlib not found")
+    def test_roundtrip_pathlib(self):
+        p = pathlib.Path(self.filename)
+        self.x.tofile(p)
+        y = np.fromfile(p, dtype=self.dtype)
+        assert_array_equal(y, self.x.flat)
+
+    @pytest.mark.skipif(pathlib is None, reason="pathlib not found")
+    def test_roundtrip_dump_pathlib(self):
+        p = pathlib.Path(self.filename)
+        self.x.dump(p)
+        y = np.load(p, allow_pickle=True)
+        assert_array_equal(y, self.x)
+
     def test_roundtrip_binary_str(self):
         s = self.x.tobytes()
         y = np.frombuffer(s, dtype=self.dtype)