Discern __str__ and __repr__ intuitively and permanently distinguish them at all.

__str__ return the string disguised body of a given object for readable of eyes
__repr__ return the real flesh body of a given object (return itself) for unambiguity to identify.

See it in an example

In [30]: str(datetime.datetime.now())
Out[30]: '2017-12-07 15:41:14.002752'
Disguised in string form

As to __repr__

In [32]: datetime.datetime.now()
Out[32]: datetime.datetime(2017, 12, 7, 15, 43, 27, 297769)
Presence in real body which allows to be manipulated directly.

We can do arithmetic operation on __repr__ results conveniently.

In [33]: datetime.datetime.now()
Out[33]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521)
In [34]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521) - datetime.datetime(2
    ...: 017, 12, 7, 15, 43, 27, 297769)
Out[34]: datetime.timedelta(0, 222, 443752)

if apply the operation on __str__

In [35]: '2017-12-07 15:43:14.002752' - '2017-12-07 15:41:14.002752'
TypeError: unsupported operand type(s) for -: 'str' and 'str'

Returns nothing but error.

Another example.

In [36]: str('string_body')
Out[36]: 'string_body' # in string form

In [37]: repr('real_body')
Out[37]: "'real_body'" #its real body hide inside

Hope this help you build concrete grounds to explore more answers.

Understand __str__ and __repr__ intuitively and permanently distinguish them at all.

__str__ return the string disguised body of a given object for readable of eyes
__repr__ return the real flesh body of a given object (return itself) for unambiguity to identify.

See it in an example

In [30]: str(datetime.datetime.now())
Out[30]: '2017-12-07 15:41:14.002752'
Disguised in string form

As to __repr__

In [32]: datetime.datetime.now()
Out[32]: datetime.datetime(2017, 12, 7, 15, 43, 27, 297769)
Presence in real body which allows to be manipulated directly.

We can do arithmetic operation on __repr__ results conveniently.

In [33]: datetime.datetime.now()
Out[33]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521)
In [34]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521) - datetime.datetime(2
    ...: 017, 12, 7, 15, 43, 27, 297769)
Out[34]: datetime.timedelta(0, 222, 443752)

if apply the operation on __str__

In [35]: '2017-12-07 15:43:14.002752' - '2017-12-07 15:41:14.002752'
TypeError: unsupported operand type(s) for -: 'str' and 'str'

Returns nothing but error.

Another example.

In [36]: str('string_body')
Out[36]: 'string_body' # in string form

In [37]: repr('real_body')
Out[37]: "'real_body'" #its real body hide inside

Hope this help you build concrete grounds to explore more answers.

Discern __str__ and __repr__ intuitively and permanently distinguish them at all.

__str__ return the string body of a given object,
__repr__ return the real body of a given object (return itself)

See it in an example

In [30]: str(datetime.datetime.now())
Out[30]: '2017-12-07 15:41:14.002752'
Disguised in string form

As to __repr__

In [32]: datetime.datetime.now()
Out[32]: datetime.datetime(2017, 12, 7, 15, 43, 27, 297769)
Presence in real body which allows to be manipulated directly.

We can do arithmetic operation on __repr__ results conveniently.

In [33]: datetime.datetime.now()
Out[33]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521)
In [34]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521) - datetime.datetime(2
    ...: 017, 12, 7, 15, 43, 27, 297769)
Out[34]: datetime.timedelta(0, 222, 443752)

if apply the operation on __str__

In [35]: '2017-12-07 15:43:14.002752' - '2017-12-07 15:41:14.002752'
TypeError: unsupported operand type(s) for -: 'str' and 'str'

Returns nothing but error.

Another example.

In [36]: str('string_body')
Out[36]: 'string_body' # in string form

In [37]: repr('real_body')
Out[37]: "'real_body'" #its real body hide inside

Hope this help you build concrete grounds to explore more answers.

Discern __str__ and __repr__ intuitively and permanently distinguish them at all.

__str__ return the string disguised body of a given object for readable of eyes
__repr__ return the real flesh body of a given object (return itself) for unambiguity to identify.

See it in an example

In [30]: str(datetime.datetime.now())
Out[30]: '2017-12-07 15:41:14.002752'
Disguised in string form

As to __repr__

In [32]: datetime.datetime.now()
Out[32]: datetime.datetime(2017, 12, 7, 15, 43, 27, 297769)
Presence in real body which allows to be manipulated directly.

We can do arithmetic operation on __repr__ results conveniently.

In [33]: datetime.datetime.now()
Out[33]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521)
In [34]: datetime.datetime(2017, 12, 7, 15, 47, 9, 741521) - datetime.datetime(2
    ...: 017, 12, 7, 15, 43, 27, 297769)
Out[34]: datetime.timedelta(0, 222, 443752)

if apply the operation on __str__

In [35]: '2017-12-07 15:43:14.002752' - '2017-12-07 15:41:14.002752'
TypeError: unsupported operand type(s) for -: 'str' and 'str'

Returns nothing but error.

Another example.

In [36]: str('string_body')
Out[36]: 'string_body' # in string form

In [37]: repr('real_body')
Out[37]: "'real_body'" #its real body hide inside

Hope this help you build concrete grounds to explore more answers.