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57 lines
1.0 KiB
Plaintext
57 lines
1.0 KiB
Plaintext
NAME
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test - whether a value is deemed to be true or false
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SYNOPSIS
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test(x)
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TYPES
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x any
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return 0 or 1
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DESCRIPTION
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This function returns 1 or 0 according as x tests as "true" or "false".
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Conditions under which a value x is considered to be false are:
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Numbers (real or complex): x is zero
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String: x == ""
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Matrix: every component of x tests as false
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List: every element of x tests as false
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Association: x has no element
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File: x is not open
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Null: always
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Object of type xx: if xx_test has been defined, xx_test(x)
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returns zero; if xx_test has not been defined,
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every element of x tests as false.
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Error-value or other types: never
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EXAMPLE
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> print test(27), test(0), test("abc"), test("")
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1 0 1 0
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> print test(mat[3] = {1,,2}), test(mat[2][2])
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1 0
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> A = list(0, 2, 0)
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> print test(A), test(pop(A)), test(A), test(pop(A)), test(A)
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1 0 1 1 0
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LIMITS
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none
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LIBRARY
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none
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SEE ALSO
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isassoc, isfile, isident, isnum, isint, islist, ismat, isnull, isobj,
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isreal, isstr, issimple, istype
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