🚧 ALTO: Move xpath_statistics to TagGroup class

qurator/modstool/altotool.py

@@ -76,27 +76,13 @@ def alto_to_dict(alto, raise_errors=True):
         elif localname == 'Layout':
             value[localname] = TagGroup(tag, group).is_singleton().has_no_attributes().descend(raise_errors)
         elif localname == 'Page':
-            value['Page'] = {}
-            value['Page'].update(TagGroup(tag, group).is_singleton().attributes())
-            value['Page'].update(TagGroup(tag, group).subelement_counts())
-
-            xpath_expr = "//alto:String/@WC"
             alto_namespace = ET.QName(group[0]).namespace
             namespaces={"alto": alto_namespace}
 
-            def xpath_statistics(xpath_expr, namespaces):
-                values = []
-                for e in group:
-                    r = e.xpath(xpath_expr, namespaces=namespaces)
-                    values += r
-                values = np.array([float(v) for v in values])
-
-                statistics = {}
-                statistics[f'{xpath_expr}-mean'] = np.mean(values)
-                return statistics
-
-            value['Page'].update(xpath_statistics(xpath_expr, namespaces))
-
+            value[localname] = {}
+            value[localname].update(TagGroup(tag, group).is_singleton().attributes())
+            value[localname].update(TagGroup(tag, group).subelement_counts())
+            value[localname].update(TagGroup(tag, group).xpath_statistics("//alto:String/@WC", namespaces))
 
         elif localname == 'Styles':
             pass

qurator/modstool/lib.py

@@ -3,6 +3,7 @@ import re
 import warnings
 from typing import List, Sequence, MutableMapping
 
+import numpy as np
 from lxml import etree as ET
 
 
@@ -206,6 +207,24 @@ class TagGroup:
                 counts[key] = counts.get(key, 0) + 1
         return counts
 
+    def xpath_statistics(self, xpath_expr, namespaces):
+        """
+        Extract values and calculate statistics
+
+        Extract values using the given XPath expression, convert them to float and return descriptive
+        statistics on the values.
+        """
+        values = []
+        for e in self.group:
+            r = e.xpath(xpath_expr, namespaces=namespaces)
+            values += r
+        values = np.array([float(v) for v in values])
+
+        statistics = {}
+        statistics[f'{xpath_expr}-mean'] = np.mean(values)
+        return statistics
+
+
 
 
 def sorted_groupby(iterable, key=None):