add dataset details to lh5.tools.show (#89)

src/lgdo/cli.py

@@ -52,6 +52,11 @@ def lh5ls(args=None):
         default=None,
         help="""Maximum tree depth of groups to print""",
     )
+    parser.add_argument(
+        "--detail",
+        action="store_true",
+        help="""Print details about datasets""",
+    )
 
     args = parser.parse_args(args)
 
@@ -66,7 +71,13 @@ def lh5ls(args=None):
         print(__version__)  # noqa: T201
         sys.exit()
 
-    lh5.show(args.lh5_file, args.lh5_group, attrs=args.attributes, depth=args.depth)
+    lh5.show(
+        args.lh5_file,
+        args.lh5_group,
+        attrs=args.attributes,
+        depth=args.depth,
+        detail=args.detail,
+    )
 
 
 def lh5concat(args=None):

src/lgdo/lh5/tools.py

@@ -87,6 +87,7 @@ def show(
     indent: str = "",
     header: bool = True,
     depth: int | None = None,
+    detail: bool = False,
 ) -> None:
     """Print a tree of LH5 file contents with LGDO datatype.
 
@@ -104,6 +105,8 @@ def show(
         print `lh5_group` at the top of the diagram.
     depth
         maximum tree depth of groups to print
+    detail
+        whether to print additional information about how the data is stored
 
     Examples
     --------
@@ -171,6 +174,26 @@ def show(
 
         print(f"{indent}{char} \033[1m{key}\033[0m · {dtype} {_attrs}")  # noqa: T201
 
+        if detail and isinstance(val, h5py.Dataset):
+            char = "|       "
+            if killme:
+                char = "        "
+            toprint = f"{indent}{char}"
+            try:
+                toprint += f"\033[3mdtype\033[0m={val.dtype}"
+                toprint += f", \033[3mshape\033[0m={val.shape}"
+                toprint += f", \033[3mnbytes\033[0m={utils.fmtbytes(val.nbytes)}"
+                if (chunkshape := val.chunks) is None:
+                    toprint += ", \033[3mnumchunks\033[0m=contiguous"
+                else:
+                    toprint += f", \033[3mnumchunks\033[0m={val.id.get_num_chunks()}"
+                    toprint += f", \033[3mchunkshape\033[0m={chunkshape}"
+                toprint += f", \033[3mcompression\033[0m={val.compression}"
+            except TypeError:
+                toprint += "(scalar)"
+
+            print(toprint)  # noqa: T201
+
         # if it's a group, call this function recursively
         if isinstance(val, h5py.Group):
             show(
@@ -179,6 +202,7 @@ def show(
                 header=False,
                 attrs=attrs,
                 depth=depth - 1 if depth else None,
+                detail=detail,
             )
 
         # break or move to next key

src/lgdo/lh5/utils.py

@@ -221,3 +221,13 @@ def expand_path(
         return paths[0]
 
     return paths
+
+
+# https://stackoverflow.com/a/1094933
+def fmtbytes(num, suffix="B"):
+    """Returns formatted f-string for printing human-readable number of bytes."""
+    for unit in ("", "k", "M", "G", "T", "P", "E", "Z"):
+        if abs(num) < 1024.0:
+            return f"{num:3.1f} {unit}{suffix}"
+        num /= 1024.0
+    return f"{num:.1f} Y{suffix}"