Truncate the show_as_cell() method for prettier output.

We also print out some placeholder if str() is not available.

Author: LTLA

src/biocutils/show_as_cell.py

@@ -22,5 +22,14 @@ def show_as_cell(x: Any, indices: Sequence[int]) -> List[str]:
     """
     output = []
     for i in indices:
-        output.append(str(x[i]))
+        try:
+            candidate = str(x[i])
+            if len(candidate) > 25:
+                candidate = candidate[:20] + "..." # pick the first two characters, whatever.
+            nl = candidate.find("\n")
+            if nl >= 0:
+                candidate = candidate[:nl] + "..."
+            output.append(candidate)
+        except:
+            output.append("####")
     return output

tests/test_show_as_cell.py

@@ -1,6 +1,33 @@
 from biocutils import show_as_cell
+import numpy
 
 
 def test_show_as_cell():
     assert show_as_cell([1, 2, 3, 4], range(4)) == ["1", "2", "3", "4"]
     assert show_as_cell([1, 2, 3, 4], [1, 3]) == ["2", "4"]
+
+    assert show_as_cell(["abcdefghijklmnopqrstuvwxy", "abcdefghijklmnopqrstuvwxyz"], [0,1]) == ["abcdefghijklmnopqrstuvwxy", "abcdefghijklmnopqrst..."]
+    assert show_as_cell(["abcdefghijkl\nmnopqrstuvwxyz", "abc\ndefghijklmnopqrstuvwxyz"], [0,1]) == ["abcdefghijkl...", "abc..."]
+
+
+def test_show_as_cell_numpy():
+    n1d = numpy.array([1,2,3,4,5])
+    assert show_as_cell(n1d, [0, 1, 4]) == ["1", "2", "5"]
+
+    # Empty arrays are processed correctly.
+    empty = numpy.ndarray((10, 0))
+    assert show_as_cell(empty, [0, 1, 4]) == ["[]", "[]", "[]"]
+    empty = numpy.ndarray((10, 20, 0))
+    assert show_as_cell(empty, [0, 1, 2, 3]) == ["[]", "[]", "[]", "[]"]
+
+    # Arrays where all other extents are 1 are processed correctly.
+    n1col = numpy.array([1,2,3,4,5]).reshape((5, 1))
+    assert show_as_cell(n1col, [2, 3]) == ["[3]", "[4]"]
+    n1col = numpy.array([1,2,3,4,5]).reshape((5, 1, 1))
+    assert show_as_cell(n1col, [1, 4]) == ["[[2]]", "[[5]]"]
+
+    # Arrays other extents are > 1 are processed correctly.
+    general = numpy.array([1,2,3,4,5,6]).reshape((3, 2))
+    assert show_as_cell(general, [0, 2]) == ["[1 2]", "[5 6]"]
+    general = numpy.array([1,2,3,4,5,6]).reshape((3, 2, 1))
+    assert show_as_cell(general, [0, 2]) == ["[[1]...", "[[5]..."]