csv parser for testing

rest_pandas/test.py

@@ -0,0 +1,58 @@
+import csv
+from .renderers import StringIO
+
+
+def parse_csv(string):
+    """
+    Rough port of wq/pandas.js to Python.  Useful for validating CSV output
+    generated by Django REST Pandas.
+    """
+    reader = csv.reader(StringIO(string))
+    val_cols = None
+    id_cols = None
+    for row in reader:
+        if row[0] == '':
+            val_cols = row[row.count(''):]
+            col_meta = [{} for v in val_cols]
+        elif row[-1] != '' and val_cols and not id_cols:
+            key = row[0]
+            for i, meta in enumerate(row[1:]):
+                col_meta[i].update(**{key: meta})
+        elif row[-1] == '':
+            id_cols = row[:row.index('')]
+            meta_index = {}
+            meta_i = 0
+            datasets = []
+            for i, ds1 in enumerate(col_meta):
+                if i in meta_index:
+                    continue
+                meta_index[i] = meta_i
+                meta_i += 1
+                datasets.append(ds1)
+                if i < len(col_meta):
+                    for j, ds2 in enumerate(col_meta[i + 1:]):
+                        if ds1 == ds2:
+                            meta_index[i + j + 1] = i
+            for d in datasets:
+                d['data'] = []
+        elif val_cols and id_cols:
+            ids = {
+                key: val
+                for key, val in zip(id_cols, row[:len(id_cols)])
+            }
+            records = {}
+            for i, val in enumerate(row[len(id_cols):]):
+                mi = meta_index[i]
+                if mi not in records:
+                    data = ids.copy()
+                else:
+                    data = records[mi]
+                try:
+                    val = float(val)
+                except ValueError:
+                    pass
+                data[val_cols[i]] = val
+                records[mi] = data
+            for mi, data in records.items():
+                datasets[mi]['data'].append(data)
+    return datasets