.. This document was generated by tools/gen-cpydiff.py
Builtin types
=============
Generated Wed 11 Nov 2020 02:26:58 UTC
Exception
---------
.. _cpydiff_types_exception_chaining:
Exception chaining not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
try:
raise TypeError
except TypeError:
raise ValueError
+-------------------------------------------------------------------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------------------------------------------------------------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| Traceback (most recent call last): | /bin/sh: ../ports/unix/micropython: No such file or directory |
| File "<stdin>", line 8, in <module> | |
| TypeError | |
| | |
| During handling of the above exception, another exception occurred: | |
| | |
| Traceback (most recent call last): | |
| File "<stdin>", line 10, in <module> | |
| ValueError | |
+-------------------------------------------------------------------------+-------------------------------------------------------------------+
.. _cpydiff_types_exception_instancevar:
User-defined attributes for builtin exceptions are not supported
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** MicroPython is highly optimized for memory usage.
**Workaround:** Use user-defined exception subclasses.
Sample code::
e = Exception()
e.x = 0
print(e.x)
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| 0 | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
.. _cpydiff_types_exception_loops:
Exception in while loop condition may have unexpected line number
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** Condition checks are optimized to happen at the end of loop body, and that line number is reported.
Sample code::
l = ["-foo", "-bar"]
i = 0
while l[i][0] == "-":
print("iter")
i += 1
+--------------------------------------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+--------------------------------------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| iter | /bin/sh: ../ports/unix/micropython: No such file or directory |
| iter | |
| Traceback (most recent call last): | |
| File "<stdin>", line 10, in <module> | |
| IndexError: list index out of range | |
+--------------------------------------------+-------------------------------------------------------------------+
.. _cpydiff_types_exception_subclassinit:
Exception.__init__ method does not exist.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** Subclassing native classes is not fully supported in MicroPython.
**Workaround:** Call using ``super()`` instead::
class A(Exception):
def __init__(self):
super().__init__()
Sample code::
class A(Exception):
def __init__(self):
Exception.__init__(self)
a = A()
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| | :: |
| | |
| | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
bytearray
---------
.. _cpydiff_types_bytearray_sliceassign:
Array slice assignment with unsupported RHS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
b = bytearray(4)
b[0:1] = [1, 2]
print(b)
+----------------------------------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+----------------------------------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| bytearray(b'\x01\x02\x00\x00\x00') | /bin/sh: ../ports/unix/micropython: No such file or directory |
+----------------------------------------+-------------------------------------------------------------------+
bytes
-----
.. _cpydiff_types_bytes_format:
bytes objects support .format() method
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** MicroPython strives to be a more regular implementation, so if both `str` and `bytes` support ``__mod__()`` (the % operator), it makes sense to support ``format()`` for both too. Support for ``__mod__`` can also be compiled out, which leaves only ``format()`` for bytes formatting.
**Workaround:** If you are interested in CPython compatibility, don't use ``.format()`` on bytes objects.
Sample code::
print(b'{}'.format(1))
+--------------------------------------------------------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+--------------------------------------------------------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| Traceback (most recent call last): | /bin/sh: ../ports/unix/micropython: No such file or directory |
| File "<stdin>", line 7, in <module> | |
| AttributeError: 'bytes' object has no attribute 'format' | |
+--------------------------------------------------------------+-------------------------------------------------------------------+
.. _cpydiff_types_bytes_keywords:
bytes() with keywords not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Workaround:** Pass the encoding as a positional parameter, e.g. ``print(bytes('abc', 'utf-8'))``
Sample code::
print(bytes('abc', encoding='utf8'))
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| b'abc' | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
.. _cpydiff_types_bytes_subscrstep:
Bytes subscription with step != 1 not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** MicroPython is highly optimized for memory usage.
**Workaround:** Use explicit loop for this very rare operation.
Sample code::
print(b'123'[0:3:2])
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| b'13' | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
dict
----
.. _cpydiff_types_dict_keys_set:
Dictionary keys view does not behave as a set.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** Not implemented.
**Workaround:** Explicitly convert keys to a set before using set operations.
Sample code::
print({1:2, 3:4}.keys() & {1})
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| {1} | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
float
-----
.. _cpydiff_types_float_rounding:
uPy and CPython outputs formats may differ
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
print('%.1g' % -9.9)
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| -1e+01 | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
int
---
.. _cpydiff_types_int_subclassconv:
No int conversion for int-derived types available
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Workaround:** Avoid subclassing builtin types unless really needed. Prefer https://en.wikipedia.org/wiki/Composition_over_inheritance .
Sample code::
class A(int):
__add__ = lambda self, other: A(int(self) + other)
a = A(42)
print(a+a)
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| 84 | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
list
----
.. _cpydiff_types_list_delete_subscrstep:
List delete with step != 1 not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Workaround:** Use explicit loop for this rare operation.
Sample code::
l = [1, 2, 3, 4]
del l[0:4:2]
print(l)
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| [2, 4] | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
.. _cpydiff_types_list_store_noniter:
List slice-store with non-iterable on RHS is not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** RHS is restricted to be a tuple or list
**Workaround:** Use ``list(<iter>)`` on RHS to convert the iterable to a list
Sample code::
l = [10, 20]
l[0:1] = range(4)
print(l)
+----------------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+----------------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| [0, 1, 2, 3, 20] | /bin/sh: ../ports/unix/micropython: No such file or directory |
+----------------------+-------------------------------------------------------------------+
.. _cpydiff_types_list_store_subscrstep:
List store with step != 1 not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Workaround:** Use explicit loop for this rare operation.
Sample code::
l = [1, 2, 3, 4]
l[0:4:2] = [5, 6]
print(l)
+------------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+------------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| [5, 2, 6, 4] | /bin/sh: ../ports/unix/micropython: No such file or directory |
+------------------+-------------------------------------------------------------------+
str
---
.. _cpydiff_types_str_endswith:
Start/end indices such as str.endswith(s, start) not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
print('abc'.endswith('c', 1))
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| True | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
.. _cpydiff_types_str_formatsubscr:
Attributes/subscr not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
print('{a[0]}'.format(a=[1, 2]))
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| 1 | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
.. _cpydiff_types_str_keywords:
str(...) with keywords not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Workaround:** Input the encoding format directly. eg ``print(bytes('abc', 'utf-8'))``
Sample code::
print(str(b'abc', encoding='utf8'))
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| abc | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
.. _cpydiff_types_str_ljust_rjust:
str.ljust() and str.rjust() not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**Cause:** MicroPython is highly optimized for memory usage. Easy workarounds available.
**Workaround:** Instead of ``s.ljust(10)`` use ``"%-10s" % s``, instead of ``s.rjust(10)`` use ``"% 10s" % s``. Alternatively, ``"{:<10}".format(s)`` or ``"{:>10}".format(s)``.
Sample code::
print('abc'.ljust(10))
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| abc | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
.. _cpydiff_types_str_rsplitnone:
None as first argument for rsplit such as str.rsplit(None, n) not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
print('a a a'.rsplit(None, 1))
+------------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+------------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| ['a a', 'a'] | /bin/sh: ../ports/unix/micropython: No such file or directory |
+------------------+-------------------------------------------------------------------+
.. _cpydiff_types_str_subscrstep:
Subscript with step != 1 is not yet implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
print('abcdefghi'[0:9:2])
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| acegi | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+
tuple
-----
.. _cpydiff_types_tuple_subscrstep:
Tuple load with step != 1 not implemented
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sample code::
print((1, 2, 3, 4)[0:4:2])
+-------------+-------------------------------------------------------------------+
| CPy output: | uPy output: |
+-------------+-------------------------------------------------------------------+
| :: | :: |
| | |
| (1, 3) | /bin/sh: ../ports/unix/micropython: No such file or directory |
+-------------+-------------------------------------------------------------------+