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⇤ ← Revision 1 as of 2012-02-16 16:27:21
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| {{{#!rst |
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| The goal of this page is to gather all problems due to equality accepting coercion in borderline cases | The goal of this page is to gather all problems due to equality accepting coercion in borderline cases:: |
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| {{{ sage: bool(pi == 3.14159265358979323) True sage: hash(pi) 2943215493 sage: hash(3.14159265358979323) 1826823505 sage: dd {3.1415926535897932: 'approx', pi: 'exact'} sage: {0:"exact", 0.0000000000000000000:"approx"} {0: 'approx'} }}} as a consequence {{{ sage: pii = 3.14159265358979323 sage: bool(pii == pi) True sage: dd = {pi: "exact"} sage: pi in dd True sage: pii in dd False sage: pii in dd.keys() True |
sage: bool(pi == 3.14159265358979323) True sage: hash(pi) 2943215493 sage: hash(3.14159265358979323) 1826823505 sage: dd {3.1415926535897932: 'approx', pi: 'exact'} sage: {0:"exact", 0.0000000000000000000:"approx"} {0: 'approx'} as a consequence:: sage: pii = 3.14159265358979323 sage: bool(pii == pi) True sage: dd = {pi: "exact"} sage: pi in dd True sage: pii in dd False sage: pii in dd.keys() True |
Equality and Coercion could be harmful
The goal of this page is to gather all problems due to equality accepting coercion in borderline cases:
sage: bool(pi == 3.14159265358979323)
True
sage: hash(pi)
2943215493
sage: hash(3.14159265358979323)
1826823505
sage: dd
{3.1415926535897932: 'approx', pi: 'exact'}
sage: {0:"exact", 0.0000000000000000000:"approx"}
{0: 'approx'}as a consequence:
sage: pii = 3.14159265358979323
sage: bool(pii == pi)
True
sage: dd = {pi: "exact"}
sage: pi in dd
True
sage: pii in dd
False
sage: pii in dd.keys()
True