Issue #6081: Add str.format_map. str.format_map(mapping) is similar t… · pythoncapi/cpython@27bbca6 · GitHub
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ericvsmithericvsmith
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Issue python#6081: Add str.format_map. str.format_map(mapping) is similar to str.format(**mapping), except mapping does not get converted to a dict.
1 parent 2397dd5 commit 27bbca6

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Lines changed: 104 additions & 1 deletion

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‎Doc/library/stdtypes.rst‎

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‎Lib/test/test_unicode.py‎

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Original file line numberDiff line numberDiff line change
@@ -695,6 +695,84 @@ def __format__(self, format_spec):
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self.assertRaises(ValueError, format, '', '#')
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self.assertRaises(ValueError, format, '', '#20')
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def test_format_map(self):
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self.assertEqual(''.format_map({}), '')
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self.assertEqual('a'.format_map({}), 'a')
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self.assertEqual('ab'.format_map({}), 'ab')
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self.assertEqual('a{{'.format_map({}), 'a{')
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self.assertEqual('a}}'.format_map({}), 'a}')
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self.assertEqual('{{b'.format_map({}), '{b')
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self.assertEqual('}}b'.format_map({}), '}b')
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self.assertEqual('a{{b'.format_map({}), 'a{b')
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# using mappings
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class Mapping(dict):
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def __missing__(self, key):
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return key
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self.assertEqual('{hello}'.format_map(Mapping()), 'hello')
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self.assertEqual('{a} {world}'.format_map(Mapping(a='hello')), 'hello world')
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class InternalMapping:
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def __init__(self):
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self.mapping = {'a': 'hello'}
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def __getitem__(self, key):
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return self.mapping[key]
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self.assertEqual('{a}'.format_map(InternalMapping()), 'hello')
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# classes we'll use for testing
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class C:
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def __init__(self, x=100):
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self._x = x
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def __format__(self, spec):
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return spec
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class D:
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def __init__(self, x):
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self.x = x
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def __format__(self, spec):
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return str(self.x)
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# class with __str__, but no __format__
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class E:
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def __init__(self, x):
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self.x = x
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def __str__(self):
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return 'E(' + self.x + ')'
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# class with __repr__, but no __format__ or __str__
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class F:
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def __init__(self, x):
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self.x = x
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def __repr__(self):
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return 'F(' + self.x + ')'
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# class with __format__ that forwards to string, for some format_spec's
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class G:
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def __init__(self, x):
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self.x = x
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def __str__(self):
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return "string is " + self.x
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def __format__(self, format_spec):
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if format_spec == 'd':
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return 'G(' + self.x + ')'
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return object.__format__(self, format_spec)
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# class that returns a bad type from __format__
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class H:
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def __format__(self, format_spec):
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return 1.0
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self.assertEqual('{foo._x}'.format_map({'foo': C(20)}), '20')
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# test various errors
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self.assertRaises(TypeError, '{'.format_map)
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self.assertRaises(TypeError, '}'.format_map)
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self.assertRaises(TypeError, 'a{'.format_map)
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self.assertRaises(TypeError, 'a}'.format_map)
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self.assertRaises(TypeError, '{a'.format_map)
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self.assertRaises(TypeError, '}a'.format_map)
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def test_format_auto_numbering(self):
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class C:
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def __init__(self, x=100):

‎Misc/NEWS‎

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@@ -10,6 +10,8 @@ What's New in Python 3.2 Beta 1?
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Core and Builtins
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-----------------
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- Issue #6081: Add str.format_map, similar to str.format(**mapping).
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- If FileIO.__init__ fails, close the file descriptor.
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- Issue #10221: dict.pop(k) now has a key error message that includes the

‎Objects/stringlib/string_format.h‎

Lines changed: 10 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -499,7 +499,11 @@ get_field_object(SubString *input, PyObject *args, PyObject *kwargs,
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PyObject *key = SubString_new_object(&first);
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if (key == NULL)
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goto error;
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if ((kwargs == NULL) || (obj = PyDict_GetItem(kwargs, key)) == NULL) {
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/* Use PyObject_GetItem instead of PyDict_GetItem because this
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code is no longer just used with kwargs. It might be passed
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a non-dict when called through format_map. */
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if ((kwargs == NULL) || (obj = PyObject_GetItem(kwargs, key)) == NULL) {
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PyErr_SetObject(PyExc_KeyError, key);
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Py_DECREF(key);
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goto error;
@@ -1039,6 +1043,11 @@ do_string_format(PyObject *self, PyObject *args, PyObject *kwargs)
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return build_string(&input, args, kwargs, recursion_depth, &auto_number);
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}
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static PyObject *
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do_string_format_map(PyObject *self, PyObject *obj)
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{
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return do_string_format(self, NULL, obj);
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}
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/************************************************************************/

‎Objects/unicodeobject.c‎

Lines changed: 6 additions & 0 deletions

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