flake8-multiline-conditionals-comprehensions

flake8 plugin that works on conditional expressions and comprehension expressions to enforce each segment to be put on a new line.

Contents

• Options
• Comprehension Errors
• Condition Errors

Options

The flag --select_mcc2 can be used to select the set of errors to include. By default, the active errors are MCC200, MCC201, MCC202, MCC220, MCC221, MCC223.

Comprehension Errors

MCC200

A comprehension expression should place each of its generators on a separate line.

# Bad
[x+y for x in range(10) for y in range(10)]

# Good
[
    x + y
    for x in range(10)
    for y in range(10)
]

MCC201

A multiline comprehension expression should place each of its segments (map, generator, filter) on a separate line.

# Bad
[x+y for x in range(10) 
for y in range(10) if x+y > 5]

# Good
[
    x + y
    for x in range(10)
    for y in range(10)
    if x + y > 5
]

MCC202

A comprehension expression should not contain multiple filters.

# Bad
[x for x in range(10) if x % 2 == 0 if x % 3 == 0]

# Good
[x for x in range(10) if x % 2 == x % 3 == 0]

MCC203

A comprehension expression should not span over multiple lines.

# Bad
[x + y 
for x in range(10) ]

# Good
[x+y for x in range(10)]

MCC204

A comprehension expression should span over multiple lines.

# Bad
[x for x in range(10)]

# Good
[x 
for x in range(10)]

Condition Errors

MCC220

A multiline conditional expression should place each of its segments on a separate line.

# Bad
1 
if something() else 0

# Good
1
if something()
else 0

MCC221

A conditional expression used for assignment should be surrounded by parantheses.

# Bad
a = 1 if something() else 0

# Good
a = (1 if something() else 0)

MCC222

A conditional expression should not contain further conditional expressions.

# Bad
1 if x > 0 else -1 if x < 0 else 0

# Good
if x > 0:
    return 1
elif x < 0:
    return -1
else:
    return 0

MCC223

A conditional expression should not span over multiple lines.

# Bad
1
if something()
else 0

# Good
1 if something() else 0

MCC224

A conditional expression should span over multiple lines.

# Bad
1 if something() else 0

# Good
1
if something()
else 0

MCC225

Conditional expressions should not be used.