alchemyst/Skogestad-Python

Never mix tabs and spaces.

The most popular way of indenting Python is with spaces only.  The
second-most popular way is with tabs only.  Code indented with a
mixture of tabs and spaces should be converted to using spaces
exclusively.  When invoking the Python command line interpreter with
the -t option, it issues warnings about code that illegally mixes
tabs and spaces.  When using -tt these warnings become errors.
These options are highly recommended!

Okay: if a == 0:\n    a = 1\n    b = 1
E101: if a == 0:\n        a = 1\n\tb = 1

On new projects, spaces-only are strongly recommended over tabs.

Okay: if True:\n    return
W191: if True:\n\treturn

Separate inline comments by at least two spaces.

An inline comment is a comment on the same line as a statement.
Inline comments should be separated by at least two spaces from the
statement. They should start with a # and a single space.

Each line of a block comment starts with a # and a single space
(unless it is indented text inside the comment).

Okay: x = x + 1  # Increment x
Okay: x = x + 1    # Increment x
Okay: # Block comment
E261: x = x + 1 # Increment x
E262: x = x + 1  #Increment x
E262: x = x + 1  #  Increment x
E265: #Block comment
E266: ### Block comment

Surround operators with a single space on either side.

- Always surround these binary operators with a single space on
  either side: assignment (=), augmented assignment (+=, -= etc.),
  comparisons (==, <, >, !=, <=, >=, in, not in, is, is not),
  Booleans (and, or, not).

- If operators with different priorities are used, consider adding
  whitespace around the operators with the lowest priorities.

Okay: i = i + 1
Okay: submitted += 1
Okay: x = x * 2 - 1
Okay: hypot2 = x * x + y * y
Okay: c = (a + b) * (a - b)
Okay: foo(bar, key='word', *args, **kwargs)
Okay: alpha[:-i]

E225: i=i+1
E225: submitted +=1
E225: x = x /2 - 1
E225: z = x **y
E225: z = 1and 1
E226: c = (a+b) * (a-b)
E226: hypot2 = x*x + y*y
E227: c = a|b
E228: msg = fmt%(errno, errmsg)

Compound statements (on the same line) are generally discouraged.

While sometimes it's okay to put an if/for/while with a small body
on the same line, never do this for multi-clause statements.
Also avoid folding such long lines!

Always use a def statement instead of an assignment statement that
binds a lambda expression directly to a name.

Okay: if foo == 'blah':\n    do_blah_thing()
Okay: do_one()
Okay: do_two()
Okay: do_three()

E701: if foo == 'blah': do_blah_thing()
E701: for x in lst: total += x
E701: while t < 10: t = delay()
E701: if foo == 'blah': do_blah_thing()
E701: else: do_non_blah_thing()
E701: try: something()
E701: finally: cleanup()
E701: if foo == 'blah': one(); two(); three()
E702: do_one(); do_two(); do_three()
E703: do_four();  # useless semicolon
E704: def f(x): return 2*x
E731: f = lambda x: 2*x

Compound statements (on the same line) are generally discouraged.

While sometimes it's okay to put an if/for/while with a small body
on the same line, never do this for multi-clause statements.
Also avoid folding such long lines!

Always use a def statement instead of an assignment statement that
binds a lambda expression directly to a name.

Okay: if foo == 'blah':\n    do_blah_thing()
Okay: do_one()
Okay: do_two()
Okay: do_three()

E701: if foo == 'blah': do_blah_thing()
E701: for x in lst: total += x
E701: while t < 10: t = delay()
E701: if foo == 'blah': do_blah_thing()
E701: else: do_non_blah_thing()
E701: try: something()
E701: finally: cleanup()
E701: if foo == 'blah': one(); two(); three()
E702: do_one(); do_two(); do_three()
E703: do_four();  # useless semicolon
E704: def f(x): return 2*x
E731: f = lambda x: 2*x

Limit all lines to a maximum of 79 characters.

There are still many devices around that are limited to 80 character
lines; plus, limiting windows to 80 characters makes it possible to
have several windows side-by-side.  The default wrapping on such
devices looks ugly.  Therefore, please limit all lines to a maximum
of 79 characters. For flowing long blocks of text (docstrings or
comments), limiting the length to 72 characters is recommended.

Reports error E501.

Trailing whitespace is superfluous.

The warning returned varies on whether the line itself is blank,
for easier filtering for those who want to indent their blank lines.

Okay: spam(1)\n#
W291: spam(1) \n#
W293: class Foo(object):\n    \n    bang = 12

Separate inline comments by at least two spaces.

An inline comment is a comment on the same line as a statement.
Inline comments should be separated by at least two spaces from the
statement. They should start with a # and a single space.

Each line of a block comment starts with a # and a single space
(unless it is indented text inside the comment).

Okay: x = x + 1  # Increment x
Okay: x = x + 1    # Increment x
Okay: # Block comment
E261: x = x + 1 # Increment x
E262: x = x + 1  #Increment x
E262: x = x + 1  #  Increment x
E265: #Block comment
E266: ### Block comment

Invalid escape sequences are deprecated in Python 3.6.

Okay: regex = r'\.png$'
W605: regex = '\.png$'

Trailing whitespace is superfluous.

The warning returned varies on whether the line itself is blank,
for easier filtering for those who want to indent their blank lines.

Okay: spam(1)\n#
W291: spam(1) \n#
W293: class Foo(object):\n    \n    bang = 12

Separate top-level function and class definitions with two blank lines.

Method definitions inside a class are separated by a single blank
line.

Extra blank lines may be used (sparingly) to separate groups of
related functions.  Blank lines may be omitted between a bunch of
related one-liners (e.g. a set of dummy implementations).

Use blank lines in functions, sparingly, to indicate logical
sections.

Okay: def a():\n    pass\n\n\ndef b():\n    pass
Okay: def a():\n    pass\n\n\nasync def b():\n    pass
Okay: def a():\n    pass\n\n\n# Foo\n# Bar\n\ndef b():\n    pass
Okay: default = 1\nfoo = 1
Okay: classify = 1\nfoo = 1

E301: class Foo:\n    b = 0\n    def bar():\n        pass
E302: def a():\n    pass\n\ndef b(n):\n    pass
E302: def a():\n    pass\n\nasync def b(n):\n    pass
E303: def a():\n    pass\n\n\n\ndef b(n):\n    pass
E303: def a():\n\n\n\n    pass
E304: @decorator\n\ndef a():\n    pass
E305: def a():\n    pass\na()
E306: def a():\n    def b():\n        pass\n    def c():\n        pass

Invalid escape sequences are deprecated in Python 3.6.

Okay: regex = r'\.png$'
W605: regex = '\.png$'

Separate top-level function and class definitions with two blank lines.

Method definitions inside a class are separated by a single blank
line.

Extra blank lines may be used (sparingly) to separate groups of
related functions.  Blank lines may be omitted between a bunch of
related one-liners (e.g. a set of dummy implementations).

Use blank lines in functions, sparingly, to indicate logical
sections.

Okay: def a():\n    pass\n\n\ndef b():\n    pass
Okay: def a():\n    pass\n\n\nasync def b():\n    pass
Okay: def a():\n    pass\n\n\n# Foo\n# Bar\n\ndef b():\n    pass
Okay: default = 1\nfoo = 1
Okay: classify = 1\nfoo = 1

E301: class Foo:\n    b = 0\n    def bar():\n        pass
E302: def a():\n    pass\n\ndef b(n):\n    pass
E302: def a():\n    pass\n\nasync def b(n):\n    pass
E303: def a():\n    pass\n\n\n\ndef b(n):\n    pass
E303: def a():\n\n\n\n    pass
E304: @decorator\n\ndef a():\n    pass
E305: def a():\n    pass\na()
E306: def a():\n    def b():\n        pass\n    def c():\n        pass

Invalid escape sequences are deprecated in Python 3.6.

Okay: regex = r'\.png$'
W605: regex = '\.png$'

Invalid escape sequences are deprecated in Python 3.6.

Okay: regex = r'\.png$'
W605: regex = '\.png$'

Trailing whitespace is superfluous.

The warning returned varies on whether the line itself is blank,
for easier filtering for those who want to indent their blank lines.

Okay: spam(1)\n#
W291: spam(1) \n#
W293: class Foo(object):\n    \n    bang = 12

Separate inline comments by at least two spaces.

An inline comment is a comment on the same line as a statement.
Inline comments should be separated by at least two spaces from the
statement. They should start with a # and a single space.

Each line of a block comment starts with a # and a single space
(unless it is indented text inside the comment).

Okay: x = x + 1  # Increment x
Okay: x = x + 1    # Increment x
Okay: # Block comment
E261: x = x + 1 # Increment x
E262: x = x + 1  #Increment x
E262: x = x + 1  #  Increment x
E265: #Block comment
E266: ### Block comment

Separate inline comments by at least two spaces.

An inline comment is a comment on the same line as a statement.
Inline comments should be separated by at least two spaces from the
statement. They should start with a # and a single space.

Each line of a block comment starts with a # and a single space
(unless it is indented text inside the comment).

Okay: x = x + 1  # Increment x
Okay: x = x + 1    # Increment x
Okay: # Block comment
E261: x = x + 1 # Increment x
E262: x = x + 1  #Increment x
E262: x = x + 1  #  Increment x
E265: #Block comment
E266: ### Block comment

Separate inline comments by at least two spaces.

An inline comment is a comment on the same line as a statement.
Inline comments should be separated by at least two spaces from the
statement. They should start with a # and a single space.

Each line of a block comment starts with a # and a single space
(unless it is indented text inside the comment).

Okay: x = x + 1  # Increment x
Okay: x = x + 1    # Increment x
Okay: # Block comment
E261: x = x + 1 # Increment x
E262: x = x + 1  #Increment x
E262: x = x + 1  #  Increment x
E265: #Block comment
E266: ### Block comment