How can a function optionally return one or more values
up vote
2
down vote
favorite
What is the preferred way to ignore an optional return values of function f()?
a)
foo, _ = f()
b)
foo = f()[0]
c)
def f(return_bar=True):
if return_bar:
return foo, bar
else:
return foo
foo = f(return_bar=False)
python return
edited Nov 9 at 18:30
Amir
4,57042348
asked May 18 '17 at 10:13
Max
3314
|
show 2 more comments
up vote
2
down vote
favorite
What is the preferred way to ignore an optional return values of function f()?
a)
foo, _ = f()
b)
foo = f()[0]
c)
def f(return_bar=True):
if return_bar:
return foo, bar
else:
return foo
foo = f(return_bar=False)
python return
edited Nov 9 at 18:30
Amir
4,57042348
asked May 18 '17 at 10:13
Max
3314
definetly notC,Ais more pythonic
– Netwave
May 18 '17 at 10:15
2
b) makes sense the most. c) is not scalable and a) just wastes space on a useless object.
– Haris
May 18 '17 at 10:15
a) is good if you want to skip value in the middle, like for path, _, files in os.walk(...)
– volcano
May 18 '17 at 10:18
@Haris what do you mean by scalable in this context?
– Max
May 18 '17 at 10:23
@Max, this cannot be a standard way of doing this because one cannot use this fro cases where a function can return 1, 2 or 3 return values.
– Haris
May 18 '17 at 10:25
|
show 2 more comments
up vote
2
down vote
favorite
up vote
2
down vote
favorite
What is the preferred way to ignore an optional return values of function f()?
a)
foo, _ = f()
b)
foo = f()[0]
c)
def f(return_bar=True):
if return_bar:
return foo, bar
else:
return foo
foo = f(return_bar=False)
python return
edited Nov 9 at 18:30
Amir
4,57042348
asked May 18 '17 at 10:13
Max
3314
What is the preferred way to ignore an optional return values of function f()?
a)
foo, _ = f()
b)
foo = f()[0]
c)
def f(return_bar=True):
if return_bar:
return foo, bar
else:
return foo
foo = f(return_bar=False)
python return
python return
edited Nov 9 at 18:30
Amir
4,57042348
asked May 18 '17 at 10:13
Max
3314
edited Nov 9 at 18:30
Amir
4,57042348
asked May 18 '17 at 10:13
Max
3314
edited Nov 9 at 18:30
Amir
4,57042348
edited Nov 9 at 18:30
Amir
4,57042348
edited Nov 9 at 18:30
Amir
4,57042348
4,57042348
asked May 18 '17 at 10:13
Max
3314
asked May 18 '17 at 10:13
Max
3314
asked May 18 '17 at 10:13
Max
3314
3314
definetly notC,Ais more pythonic
– Netwave
May 18 '17 at 10:15
2
b) makes sense the most. c) is not scalable and a) just wastes space on a useless object.
– Haris
May 18 '17 at 10:15
a) is good if you want to skip value in the middle, like for path, _, files in os.walk(...)
– volcano
May 18 '17 at 10:18
@Haris what do you mean by scalable in this context?
– Max
May 18 '17 at 10:23
@Max, this cannot be a standard way of doing this because one cannot use this fro cases where a function can return 1, 2 or 3 return values.
– Haris
May 18 '17 at 10:25
|
show 2 more comments
definetly notC,Ais more pythonic
– Netwave
May 18 '17 at 10:15
2
b) makes sense the most. c) is not scalable and a) just wastes space on a useless object.
– Haris
May 18 '17 at 10:15
a) is good if you want to skip value in the middle, like for path, _, files in os.walk(...)
– volcano
May 18 '17 at 10:18
@Haris what do you mean by scalable in this context?
– Max
May 18 '17 at 10:23
@Max, this cannot be a standard way of doing this because one cannot use this fro cases where a function can return 1, 2 or 3 return values.
– Haris
May 18 '17 at 10:25
definetly not
C, A is more pythonic– Netwave
May 18 '17 at 10:15
definetly not
C, A is more pythonic– Netwave
May 18 '17 at 10:15
2
2
b) makes sense the most. c) is not scalable and a) just wastes space on a useless object.
– Haris
May 18 '17 at 10:15
b) makes sense the most. c) is not scalable and a) just wastes space on a useless object.
– Haris
May 18 '17 at 10:15
a) is good if you want to skip value in the middle, like for path, _, files in os.walk(...)
– volcano
May 18 '17 at 10:18
a) is good if you want to skip value in the middle, like for path, _, files in os.walk(...)
– volcano
May 18 '17 at 10:18
@Haris what do you mean by scalable in this context?
– Max
May 18 '17 at 10:23
@Haris what do you mean by scalable in this context?
– Max
May 18 '17 at 10:23
@Max, this cannot be a standard way of doing this because one cannot use this fro cases where a function can return 1, 2 or 3 return values.
– Haris
May 18 '17 at 10:25
@Max, this cannot be a standard way of doing this because one cannot use this fro cases where a function can return 1, 2 or 3 return values.
– Haris
May 18 '17 at 10:25
|
show 2 more comments
1 Answer
1
active
oldest
votes
up vote
3
down vote
You're setting yourself up for trouble if your function returns two variables sometimes and one variable another time.
foo, _ = f()
Usually using underscore to ignore variables is the standard practice, but in your case, if for whatever reason, this call to f() returned only one variable, you will get a runtime error.
Unless you can guarantee that f() will return two variables this time, it's better to do this
b = f()
if(isinstance(b, tuple)):
foo = b[0]
edited Nov 9 at 18:50
Amir
4,57042348
answered May 18 '17 at 10:18
ハセン
27915
3
"if this call to f() returned only one variable, you will get a runtime error."foo, *_ = f()solves this on Python 3._would simply be an empty list.
– DeepSpace
May 18 '17 at 10:20
1
where is thebcoming from? is this a typo?
– user463035818
Aug 29 at 16:17
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
You're setting yourself up for trouble if your function returns two variables sometimes and one variable another time.
foo, _ = f()
Usually using underscore to ignore variables is the standard practice, but in your case, if for whatever reason, this call to f() returned only one variable, you will get a runtime error.
Unless you can guarantee that f() will return two variables this time, it's better to do this
b = f()
if(isinstance(b, tuple)):
foo = b[0]
edited Nov 9 at 18:50
Amir
4,57042348
answered May 18 '17 at 10:18
ハセン
27915
3
"if this call to f() returned only one variable, you will get a runtime error."foo, *_ = f()solves this on Python 3._would simply be an empty list.
– DeepSpace
May 18 '17 at 10:20
1
where is thebcoming from? is this a typo?
– user463035818
Aug 29 at 16:17
add a comment |
up vote
3
down vote
You're setting yourself up for trouble if your function returns two variables sometimes and one variable another time.
foo, _ = f()
Usually using underscore to ignore variables is the standard practice, but in your case, if for whatever reason, this call to f() returned only one variable, you will get a runtime error.
Unless you can guarantee that f() will return two variables this time, it's better to do this
b = f()
if(isinstance(b, tuple)):
foo = b[0]
edited Nov 9 at 18:50
Amir
4,57042348
answered May 18 '17 at 10:18
ハセン
27915
3
"if this call to f() returned only one variable, you will get a runtime error."foo, *_ = f()solves this on Python 3._would simply be an empty list.
– DeepSpace
May 18 '17 at 10:20
1
where is thebcoming from? is this a typo?
– user463035818
Aug 29 at 16:17
add a comment |
up vote
3
down vote
up vote
3
down vote
You're setting yourself up for trouble if your function returns two variables sometimes and one variable another time.
foo, _ = f()
Usually using underscore to ignore variables is the standard practice, but in your case, if for whatever reason, this call to f() returned only one variable, you will get a runtime error.
Unless you can guarantee that f() will return two variables this time, it's better to do this
b = f()
if(isinstance(b, tuple)):
foo = b[0]
edited Nov 9 at 18:50
Amir
4,57042348
answered May 18 '17 at 10:18
ハセン
27915
You're setting yourself up for trouble if your function returns two variables sometimes and one variable another time.
foo, _ = f()
Usually using underscore to ignore variables is the standard practice, but in your case, if for whatever reason, this call to f() returned only one variable, you will get a runtime error.
Unless you can guarantee that f() will return two variables this time, it's better to do this
b = f()
if(isinstance(b, tuple)):
foo = b[0]
edited Nov 9 at 18:50
Amir
4,57042348
answered May 18 '17 at 10:18
ハセン
27915
edited Nov 9 at 18:50
Amir
4,57042348
edited Nov 9 at 18:50
Amir
4,57042348
edited Nov 9 at 18:50
Amir
4,57042348
4,57042348
answered May 18 '17 at 10:18
ハセン
27915
answered May 18 '17 at 10:18
ハセン
27915
answered May 18 '17 at 10:18
ハセン
27915
27915
3
"if this call to f() returned only one variable, you will get a runtime error."foo, *_ = f()solves this on Python 3._would simply be an empty list.
– DeepSpace
May 18 '17 at 10:20
1
where is thebcoming from? is this a typo?
– user463035818
Aug 29 at 16:17
add a comment |
3
"if this call to f() returned only one variable, you will get a runtime error."foo, *_ = f()solves this on Python 3._would simply be an empty list.
– DeepSpace
May 18 '17 at 10:20
1
where is thebcoming from? is this a typo?
– user463035818
Aug 29 at 16:17
3
3
"if this call to f() returned only one variable, you will get a runtime error."
foo, *_ = f() solves this on Python 3. _ would simply be an empty list.– DeepSpace
May 18 '17 at 10:20
"if this call to f() returned only one variable, you will get a runtime error."
foo, *_ = f() solves this on Python 3. _ would simply be an empty list.– DeepSpace
May 18 '17 at 10:20
1
1
where is the
b coming from? is this a typo?– user463035818
Aug 29 at 16:17
where is the
b coming from? is this a typo?– user463035818
Aug 29 at 16:17
add a comment |
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definetly not
C,Ais more pythonic– Netwave
May 18 '17 at 10:15
2
b) makes sense the most. c) is not scalable and a) just wastes space on a useless object.
– Haris
May 18 '17 at 10:15
a) is good if you want to skip value in the middle, like for path, _, files in os.walk(...)
– volcano
May 18 '17 at 10:18
@Haris what do you mean by scalable in this context?
– Max
May 18 '17 at 10:23
@Max, this cannot be a standard way of doing this because one cannot use this fro cases where a function can return 1, 2 or 3 return values.
– Haris
May 18 '17 at 10:25