Added a optional default argument to to_bool. Closes #238

tests/test_operations.py

@@ -117,3 +117,51 @@ def test_difference():
 
     c = a - b
     assert list(c.items()) == [(0, 0), (1, -1), (2, 1), (3, 0)]
+
+
+def test_to_bool_default():
+    data = [(0, 0), (2, 5), (3, 0), (4, 7), (10, 3)]
+
+    assert TimeSeries(data=data, default=None).to_bool().default is None
+    assert TimeSeries(data=data, default=None).to_bool()[-1] is None
+    assert TimeSeries(data=data, default=0).to_bool().default == 0
+    assert TimeSeries(data=data, default=0).to_bool()[-1] == 0
+    assert TimeSeries(data=data, default=5).to_bool().default == 1
+    assert TimeSeries(data=data, default=5).to_bool()[-1] == 1
+
+    assert (
+        TimeSeries(data=data, default=None).to_bool(default=None).default
+        is None
+    )
+    assert (
+        TimeSeries(data=data, default=0).to_bool(default=None).default is None
+    )
+    assert (
+        TimeSeries(data=data, default=5).to_bool(default=None).default is None
+    )
+
+    assert (
+        TimeSeries(data=data, default=None).to_bool(default=False).default
+        is False
+    )
+    assert (
+        TimeSeries(data=data, default=0).to_bool(default=False).default is False
+    )
+    assert (
+        TimeSeries(data=data, default=5).to_bool(default=False).default is False
+    )
+
+    assert (
+        TimeSeries(data=data, default=None).to_bool(default=True).default
+        is True
+    )
+    assert (
+        TimeSeries(data=data, default=0).to_bool(default=True).default is True
+    )
+    assert (
+        TimeSeries(data=data, default=5).to_bool(default=True).default is True
+    )
+
+    assert TimeSeries(data=data, default=None).to_bool(default=10).default == 10
+    assert TimeSeries(data=data, default=0).to_bool(default=10).default == 10
+    assert TimeSeries(data=data, default=5).to_bool(default=10).default == 10

traces/timeseries.py

@@ -17,6 +17,8 @@
 
 from . import histogram, operations, plot, utils
 
+NotGiven = object()
+
 
 class TimeSeries:
     """A class to help manipulate and analyze time series that are the
@@ -868,19 +870,44 @@ def operation(self, other, function, **kwargs):
                 result[time] = function(value, other)
         return result
 
-    def to_bool(self, invert=False):
-        """Return the truth value of each element."""
+    def to_bool(self, invert=False, default=NotGiven):
+        """Return the truth value of each element.
+
+
+        Args:
+
+            invert: opposite truth values
+
+            default: If default is not explicitly given, keep it as
+             None if it's None (which often means "undefined" rather
+             than "false"), otherwise cast to bool
+
+        Returns:
+
+            :obj:`TimeSeries` with the results.
+
+        """
+        if default is NotGiven:
+            if self.default is None:
+                new_default = None
+            else:
+                new_default = bool(self.default)
+                if invert:
+                    new_default = not (new_default)
+        else:
+            # should this complain if default not in {None, True, False}?
+            new_default = default
+
         if invert:
 
             def function(x, y):
                 return not bool(x)
-
         else:
 
             def function(x, y):
                 return bool(x)
 
-        return self.operation(None, function)
+        return self.operation(None, function, default=new_default)
 
     def threshold(self, value, inclusive=False):
         """Return True if > than treshold value (or >= threshold value if