Merge pull request #1878 from nx10/cleanup-trstr2float

Refactor TR_string_to_float

Author: nx10

CPAC/nuisance/tests/utils/test_compcor.py

@@ -0,0 +1,25 @@
+import pytest
+
+from CPAC.nuisance.utils import compcor
+
+
+def test_TR_string_to_float():
+    assert abs(compcor.TR_string_to_float('123') - 123.) < 1e-08
+    assert abs(compcor.TR_string_to_float('123s') - 123.) < 1e-08
+    assert abs(compcor.TR_string_to_float('123ms') - 123. / 1000) < 1e-08
+
+    assert abs(compcor.TR_string_to_float('1.23') - 1.23) < 1e-08
+    assert abs(compcor.TR_string_to_float('1.23s') - 1.23) < 1e-08
+    assert abs(compcor.TR_string_to_float('1.23ms') - 1.23 / 1000) < 1e-08
+
+    with pytest.raises(Exception):
+        compcor.TR_string_to_float(None)
+
+    with pytest.raises(Exception):
+        compcor.TR_string_to_float(['123'])
+
+    with pytest.raises(Exception):
+        compcor.TR_string_to_float(123)
+
+    with pytest.raises(Exception):
+        compcor.TR_string_to_float('ms')

CPAC/nuisance/utils/compcor.py

@@ -181,9 +181,32 @@ def fallback_svd(a, full_matrices=True, compute_uv=True):
 
 
 def TR_string_to_float(tr):
-    if 'ms' in tr:
-        tr = float(tr.replace('ms', '')) / 1000
-    else:
-        tr = float(tr.replace('s', ''))
+    """
+    Convert TR string to seconds (float). Suffixes 's' or 'ms' to indicate
+    seconds or milliseconds.
+
+    Parameters
+    ----------
+    tr : TR string representation. May use suffixes 's' or 'ms' to indicate
+    seconds or milliseconds.
+
+    Returns
+    -------
+    tr in seconds (float)
+    """
+    if not isinstance(tr, str):
+        raise TypeError(f'Improper type for TR_string_to_float ({tr}).')
 
-    return tr
+    tr_str = tr.replace(' ', '')
+
+    try:
+        if tr_str.endswith('ms'):
+            tr_numeric = float(tr_str[:-2]) * 0.001
+        elif tr.endswith('s'):
+            tr_numeric = float(tr_str[:-1])
+        else:
+            tr_numeric = float(tr_str)
+    except Exception as exc:
+        raise ValueError(f'Can not convert TR string to float: "{tr}".') from exc
+
+    return tr_numeric