[Python-checkins] cpython (merge 3.5 -> default): merge

[raymond.hettinger]

https://hg.python.org/cpython/rev/1b3a987d6df0
changeset:   102631:1b3a987d6df0
parent:      102628:61c4dbec2e2c
parent:      102630:de2a9c98948e
user:        Raymond Hettinger <python at rcn.com>
date:        Sat Aug 13 11:15:59 2016 -0700
summary:
  merge

files:
  Doc/library/decimal.rst |  18 ++++++++++-----
  Lib/_pydecimal.py       |  33 ++++++++++++++++++++++------
  2 files changed, 38 insertions(+), 13 deletions(-)


diff --git a/Doc/library/decimal.rst b/Doc/library/decimal.rst
--- a/Doc/library/decimal.rst
+++ b/Doc/library/decimal.rst
@@ -849,11 +849,13 @@
 
    .. method:: to_eng_string(context=None)
 
-      Convert to an engineering-type string.
-
-      Engineering notation has an exponent which is a multiple of 3, so there
-      are up to 3 digits left of the decimal place.  For example, converts
-      ``Decimal('123E+1')`` to ``Decimal('1.23E+3')``.
+      Convert to a string, using engineering notation if an exponent is needed.
+
+      Engineering notation has an exponent which is a multiple of 3.  This
+      can leave up to 3 digits to the left of the decimal place and may
+      require the addition of either one or two trailing zeros.
+
+      For example, this converts ``Decimal('123E+1')`` to ``Decimal('1.23E+3')``.
 
    .. method:: to_integral(rounding=None, context=None)
 
@@ -1423,7 +1425,11 @@
 
    .. method:: to_eng_string(x)
 
-      Converts a number to a string, using scientific notation.
+      Convert to a string, using engineering notation if an exponent is needed.
+
+      Engineering notation has an exponent which is a multiple of 3.  This
+      can leave up to 3 digits to the left of the decimal place and may
+      require the addition of either one or two trailing zeros.
 
 
    .. method:: to_integral_exact(x)
diff --git a/Lib/_pydecimal.py b/Lib/_pydecimal.py
--- a/Lib/_pydecimal.py
+++ b/Lib/_pydecimal.py
@@ -1118,12 +1118,11 @@
         return sign + intpart + fracpart + exp
 
     def to_eng_string(self, context=None):
-        """Convert to engineering-type string.
-
-        Engineering notation has an exponent which is a multiple of 3, so there
-        are up to 3 digits left of the decimal place.
-
-        Same rules for when in exponential and when as a value as in __str__.
+        """Convert to a string, using engineering notation if an exponent is needed.
+
+        Engineering notation has an exponent which is a multiple of 3.  This
+        can leave up to 3 digits to the left of the decimal place and may
+        require the addition of either one or two trailing zeros.
         """
         return self.__str__(eng=True, context=context)
 
@@ -5552,9 +5551,29 @@
             return r
 
     def to_eng_string(self, a):
-        """Converts a number to a string, using scientific notation.
+        """Convert to a string, using engineering notation if an exponent is needed.
+
+        Engineering notation has an exponent which is a multiple of 3.  This
+        can leave up to 3 digits to the left of the decimal place and may
+        require the addition of either one or two trailing zeros.
 
         The operation is not affected by the context.
+
+        >>> ExtendedContext.to_eng_string(Decimal('123E+1'))
+        '1.23E+3'
+        >>> ExtendedContext.to_eng_string(Decimal('123E+3'))
+        '123E+3'
+        >>> ExtendedContext.to_eng_string(Decimal('123E-10'))
+        '12.3E-9'
+        >>> ExtendedContext.to_eng_string(Decimal('-123E-12'))
+        '-123E-12'
+        >>> ExtendedContext.to_eng_string(Decimal('7E-7'))
+        '700E-9'
+        >>> ExtendedContext.to_eng_string(Decimal('7E+1'))
+        '70'
+        >>> ExtendedContext.to_eng_string(Decimal('0E+1'))
+        '0.00E+3'
+
         """
         a = _convert_other(a, raiseit=True)
         return a.to_eng_string(context=self)

-- 
Repository URL: https://hg.python.org/cpython