updated load api to take format as an option else infer from extension

python/src/load.cpp

@@ -6,7 +6,6 @@
 #include <cstring>
 #include <fstream>
 #include <stdexcept>
-#include <string>
 #include <string_view>
 #include <unordered_map>
 #include <vector>
@@ -179,14 +178,18 @@ std::unordered_map<std::string, array> mlx_load_safetensor_helper(
   }
 
   throw std::invalid_argument(
-      "[load] Input must be a file-like object, string, or pathlib.Path");
+      "[load_safetensor] Input must be a file-like object, string, or pathlib.Path");
 }
 
-DictOrArray mlx_load_helper(py::object file, StreamOrDevice s) {
+std::unordered_map<std::string, array> mlx_load_npz_helper(
+    py::object file,
+    StreamOrDevice s) {
   py::module_ zipfile = py::module_::import("zipfile");
-
-  // Assume .npz file if it is zipped
-  if (is_zip_file(zipfile, file)) {
+  if (!is_zip_file(zipfile, file)) {
+    throw std::invalid_argument(
+        "[load_npz] Input must be a zip file or a file-like object that can be "
+        "opened with zipfile.ZipFile");
+  }
   // Output dictionary filename in zip -> loaded array
   std::unordered_map<std::string, array> array_dict;
 
@@ -215,7 +218,10 @@ DictOrArray mlx_load_helper(py::object file, StreamOrDevice s) {
   }
 
   return {array_dict};
-  } else if (py::isinstance<py::str>(file)) { // Assume .npy file path string
+}
+
+array mlx_load_npy_helper(py::object file, StreamOrDevice s) {
+  if (py::isinstance<py::str>(file)) { // Assume .npy file path string
     return {load(py::cast<std::string>(file), s)};
   } else if (is_istream_object(file)) {
     // If we don't own the stream and it was passed to us, eval immediately
@@ -226,10 +232,40 @@ DictOrArray mlx_load_helper(py::object file, StreamOrDevice s) {
     }
     return {arr};
   }
+}
 
+DictOrArray mlx_load_helper(
+    py::object file,
+    std::optional<std::string> format,
+    StreamOrDevice s) {
+  if (!format.has_value()) {
+    std::string fname;
+    if (py::isinstance<py::str>(file)) {
+      fname = py::cast<std::string>(file);
+    } else if (is_istream_object(file)) {
+      fname = file.attr("name").cast<std::string>();
+    } else {
       throw std::invalid_argument(
           "[load] Input must be a file-like object, string, or pathlib.Path");
     }
+    size_t ext = fname.find_last_of('.');
+    if (ext == std::string::npos) {
+      throw std::invalid_argument(
+          "[load] Could not infer file format from extension");
+    }
+    format.emplace(fname.substr(ext + 1));
+  }
+
+  if (format.value() == "safetensors") {
+    return mlx_load_safetensor_helper(file, s);
+  } else if (format.value() == "npz") {
+    return mlx_load_npz_helper(file, s);
+  } else if (format.value() == "npy") {
+    return mlx_load_npy_helper(file, s);
+  } else {
+    throw std::invalid_argument("[load] Unknown file format " + format.value());
+  }
+}
 
 ///////////////////////////////////////////////////////////////////////////////
 // Saving

python/src/load.h

@@ -3,6 +3,8 @@
 #pragma once
 
 #include <pybind11/pybind11.h>
+#include <optional>
+#include <string>
 #include <unordered_map>
 #include <variant>
 #include "mlx/ops.h"

python/src/ops.cpp

@@ -2931,38 +2931,22 @@ void init_ops(py::module_& m) {
       "load",
       &mlx_load_helper,
       "file"_a,
+      "format"_a = none,
       py::pos_only(),
       py::kw_only(),
       "stream"_a = none,
       R"pbdoc(
-        load(file: str, /, *, stream: Union[None, Stream, Device] = None) -> Union[array, Dict[str, array]]
+        load(file: str, format: Optional[str] = None, /, *, stream: Union[None, Stream, Device] = None) -> Union[array, Dict[str, array]]
 
         Load array(s) from a binary file in ``.npy`` or ``.npz`` format.
 
         Args:
             file (file, str): File in which the array is saved
-
+            format (str, optional): Format of the file. If ``None``, the format
+              is inferred from the file extension. Supported formats: npy, npz, and safetensors. (default: ``None``)
         Returns:
             result (array, dict): The loaded array if ``.npy`` file or a dict mapping name to array if ``.npz`` file
       )pbdoc");
-  m.def(
-      "load_safetensor",
-      &mlx_load_safetensor_helper,
-      "file"_a,
-      py::pos_only(),
-      py::kw_only(),
-      "stream"_a = none,
-      R"pbdoc(
-        load_safetensor(file: str, /, *, stream: Union[None, Stream, Device] = None) -> Dict[str, array]
-
-        Load array(s) from a binary file in ``.safetensors`` format.
-
-        Args:
-            file (file, str): File in which the array is saved
-
-        Returns:
-            result dict: The loaded dict mapping name to array from the ``.safetensors`` file
-      )pbdoc");
   m.def(
       "save_safetensor",
       &mlx_save_safetensor_helper,