minor tweaks to print_dict_table

piccolo/utils/printing.py

@@ -1,7 +1,7 @@
 from typing import List
 
 
-def get_fixed_length_string(string: str, length=20) -> str:
+def get_fixed_length_string(string: str, length: int = 20) -> str:
     """
     Add spacing to the end of the string so it's a fixed length, or truncate
     if it's too long.
@@ -24,26 +24,34 @@ def print_heading(string: str, width: int = 64) -> None:
 def print_dict_table(data: List[dict], header_separator: bool = False) -> None:
     """
     Prints out a list of dictionaries in tabular form.
-    Uses the first list element to extract the
-    column names and their order within the row.
+
+    Uses the first list element to extract the column names and their order
+    within the row.
+
     """
-    ref_order = [column for column in data[0]]
-    width = {column: len(str(column)) for column in ref_order}
+    if len(data) == 0:
+        raise ValueError("The data must have at least one element.")
+
+    column_names = data[0].keys()
+    widths = {column_name: len(column_name) for column_name in column_names}
 
     for item in data:
-        for column in ref_order:
-            if len(str(item[column])) > width[column]:
-                width[column] = len(str(item[column]))
+        for column in column_names:
+            width = len(str(item[column]))
+            if width > widths[column]:
+                widths[column] = width
 
-    format_string = " | ".join([f"{{:<{width[w]}}}" for w in ref_order])
+    format_string = " | ".join(f"{{:<{widths[w]}}}" for w in column_names)
 
-    print(format_string.format(*[str(w) for w in ref_order]))
+    print(format_string.format(*[str(w) for w in column_names]))
 
     if header_separator:
         format_string_sep = "-+-".join(
-            [f"{{:<{width[w]}}}" for w in ref_order]
+            [f"{{:<{widths[w]}}}" for w in column_names]
+        )
+        print(
+            format_string_sep.format(*["-" * widths[w] for w in column_names])
         )
-        print(format_string_sep.format(*["-" * width[w] for w in ref_order]))
 
     for item in data:
-        print(format_string.format(*[str(item[w]) for w in ref_order]))
+        print(format_string.format(*[str(item[w]) for w in column_names]))