BUG: Display precision doesn't affect complex float numbers pandas-dev#25514

Author: sakarpanta

pandas/core/frame.py

@@ -2498,12 +2498,12 @@ def memory_usage(self, index=True, deep=False):
         ...              for t in dtypes])
         >>> df = pd.DataFrame(data)
         >>> df.head()
-           int64  float64  complex128 object  bool
-        0      1      1.0      (1+0j)      1  True
-        1      1      1.0      (1+0j)      1  True
-        2      1      1.0      (1+0j)      1  True
-        3      1      1.0      (1+0j)      1  True
-        4      1      1.0      (1+0j)      1  True
+           int64  float64              complex128 object  bool
+        0      1      1.0      1.000000+0.000000j      1  True
+        1      1      1.0      1.000000+0.000000j      1  True
+        2      1      1.0      1.000000+0.000000j      1  True
+        3      1      1.0      1.000000+0.000000j      1  True
+        4      1      1.0      1.000000+0.000000j      1  True
 
         >>> df.memory_usage()
         Index            80

pandas/io/formats/format.py

@@ -16,9 +16,9 @@
 from pandas.compat import StringIO, lzip, map, u, zip
 
 from pandas.core.dtypes.common import (
-    is_categorical_dtype, is_datetime64_dtype, is_datetime64tz_dtype,
-    is_extension_array_dtype, is_float, is_float_dtype, is_integer,
-    is_integer_dtype, is_list_like, is_numeric_dtype, is_scalar,
+    is_categorical_dtype, is_complex_dtype, is_datetime64_dtype,
+    is_datetime64tz_dtype, is_extension_array_dtype, is_float, is_float_dtype,
+    is_integer, is_integer_dtype, is_list_like, is_numeric_dtype, is_scalar,
     is_timedelta64_dtype)
 from pandas.core.dtypes.generic import (
     ABCIndexClass, ABCMultiIndex, ABCSeries, ABCSparseArray)
@@ -885,6 +885,8 @@ def format_array(values, formatter, float_format=None, na_rep='NaN',
         fmt_klass = ExtensionArrayFormatter
     elif is_float_dtype(values.dtype):
         fmt_klass = FloatArrayFormatter
+    elif is_complex_dtype(values.dtype):
+        fmt_klass = FloatArrayFormatter
     elif is_integer_dtype(values.dtype):
         fmt_klass = IntArrayFormatter
     else:

pandas/tests/io/formats/test_format.py

@@ -1417,6 +1417,18 @@ def test_to_string_float_index(self):
                     '5.0  4')
         assert result == expected
 
+    def test_to_string_complex_float_formatting(self):
+        fmt.set_option('display.precision', 5)
+        df = DataFrame({'x': [
+            (0.4467846931321966 + 0.0715185102060818j),
+            (0.2739442392974528 + 0.23515228785438969j),
+            (0.26974928742135185 + 0.3250604054898979j)]})
+        result = df.to_string()
+        expected = ('                  x\n0  0.44678+0.07152j\n'
+                    '1  0.27394+0.23515j\n'
+                    '2  0.26975+0.32506j')
+        assert result == expected
+
     def test_to_string_ascii_error(self):
         data = [('0  ', u('                        .gitignore '), u('     5 '),
                  ' \xe2\x80\xa2\xe2\x80\xa2\xe2\x80'