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Could anyone explain this unexpected behaviour of the interface?

asked 2018-06-05 10:48:02 -0500

zivaoupas gravatar image

Input

w = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]
w

Output

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]

Input

w = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]
w

Output

[0,
 1,
 2,
 3,
 4,
 5,
 6,
 7,
 8,
 9,
 10,
 11,
 12,
 13,
 14,
 15,
 16,
 17,
 18,
 19,
 20,
 21,
 22]
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3 answers

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4

answered 2018-06-05 13:17:09 -0500

slelievre gravatar image

updated 2018-06-06 00:14:06 -0500

The display of lists seems to get extra newline characters when they go over a certain number of elements.

But you can get a unified behaviour by using print, str or repr.

sage: a = list(range(22))
sage: b = list(range(23))

sage: print(a)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]
sage: print(b)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]

sage: repr(a)
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]'
sage: repr(b)
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]'

sage: str(a)
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]'
sage: str(b)
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]'

sage: a.__repr__()
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]'
sage: b.__repr__()
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]'

sage: a.__str__()
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]'
sage: b.__str__()
'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]'

Edit (after reading @Sébastien's answer and the stackoverflow answer mentioned in it). Note that what makes the pretty printing of the list get extra newline characters is not the length of the list, but whether its string representation goes over 79 characters.

sage: c = list(range(12345678901234, 12345678901239))
sage: len(c)
5
sage: len(str(c))
80
sage: c
[12345678901234,
 12345678901235,
 12345678901236,
 12345678901237,
 12345678901238]
sage: print(c)
[12345678901234, 12345678901235, 12345678901236, 12345678901237, 12345678901238]

Note that this was asked before on Ask Sage:

and there is a Sage Trac ticket about this

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2

answered 2018-06-06 10:57:58 -0500

Nicolas M. Thiéry gravatar image

See also this IPython issue: https://github.com/ipython/ipython/is...

One way to work around is to use ascii art output:

sage: %display unicode_art
sage: list(range(100))
[ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,

 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,

 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,

 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,

 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71,

 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85,

 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 ]
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2

answered 2018-06-05 15:16:23 -0500

Sébastien gravatar image

updated 2018-06-05 15:23:21 -0500

As answered here, it should be possible to turn off the pretty printing as in IPython:

$ sage -ipython
Python 2.7.15 (default, May 20 2018, 23:45:14) 
Type "copyright", "credits" or "license" for more information.

IPython 5.5.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: range(23)
Out[1]: 
[0,
 1,
 2,
 3,
 4,
 5,
 6,
 7,
 8,
 9,
 10,
 11,
 12,
 13,
 14,
 15,
 16,
 17,
 18,
 19,
 20,
 21,
 22]

In [2]: %pprint
Pretty printing has been turned OFF

In [3]: range(23)
Out[3]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]

but unfortunately, it does not work in Sage (bug?)

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Comments

Thanks @Sébastien for the extra information and pointers. I was really hoping someone would dig further than my brief "workaround" answer. Digging even a little further, I located a Sage Trac ticket for this bug (see my edited answer).

slelievre gravatar imageslelievre ( 2018-06-06 00:15:57 -0500 )edit

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Asked: 2018-06-05 10:48:02 -0500

Seen: 65 times

Last updated: Jun 06