DOC: Improve reshape\concat

DOC: Improve reshape\concat

Author: anetakahle

pandas/core/reshape/concat.py

@@ -173,6 +173,7 @@ def concat(
         they are all None in which case a ValueError will be raised.
     axis : {0/'index', 1/'columns'}, default 0
         The axis to concatenate along.
+        If 0, the outcome is identical to :meth:`DataFrame.append`.
     join : {'inner', 'outer'}, default 'outer'
         How to handle indexes on other axis (or axes).
     ignore_index : bool, default False
@@ -344,6 +345,22 @@ def concat(
     Traceback (most recent call last):
         ...
     ValueError: Indexes have overlapping values: ['a']
+
+    Append a single row to the end of a ``DataFrame`` object.
+
+    >>> a = pd.DataFrame({"A": 1, "B": 2}, index=[0])
+    >>> a
+        A   B
+    0   1   2
+    >>> b = pd.DataFrame({"A": 3}, index=[0])
+    >>> b
+        A
+    0   3
+    >>> for rowIndex, row in b.iterrows():
+    >>>     print(pd.concat([a, row.to_frame().T], ignore_index=True))
+       A    B
+    0  1  2.0
+    1  3  NaN
     """
     op = _Concatenator(
         objs,