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  2. pandas (software) - Wikipedia

    en.wikipedia.org/wiki/Pandas_(software)

    Pandas (styled as pandas) is a software library written for the Python programming language for data manipulation and analysis. In particular, it offers data structures and operations for manipulating numerical tables and time series .

  3. Missing data - Wikipedia

    en.wikipedia.org/wiki/Missing_data

    Missing not at random (MNAR) (also known as nonignorable nonresponse) is data that is neither MAR nor MCAR (i.e. the value of the variable that's missing is related to the reason it's missing). [5] To extend the previous example, this would occur if men failed to fill in a depression survey because of their level of depression.

  4. NaN - Wikipedia

    en.wikipedia.org/wiki/NaN

    In computing, NaN (/ n æ n /), standing for Not a Number, is a particular value of a numeric data type (often a floating-point number) which is undefined as a number, such as the result of 0/0.

  5. Division by zero - Wikipedia

    en.wikipedia.org/wiki/Division_by_zero

    A NaN (not a number) value represents undefined results. In IEEE arithmetic, division of 0/0 or ∞/∞ results in NaN, but otherwise division always produces a well-defined result. Dividing any non-zero number by positive zero (+0) results in an infinity of the same sign as the dividend.

  6. Data validation - Wikipedia

    en.wikipedia.org/wiki/Data_validation

    This check is essential for programs that use file handling. Format check Checks that the data is in a specified format (template), e.g., dates have to be in the format YYYY-MM-DD. Regular expressions may be used for this kind of validation. Presence check Checks that data is present, e.g., customers may be required to have an email address ...

  7. Null (SQL) - Wikipedia

    en.wikipedia.org/wiki/Null_(SQL)

    The answer may be "zero" (we know that he owns none) or "null" (we do not know how many he owns). In a database table, the column reporting this answer would start with no value (marked by null), and it would not be updated with the value zero until it is ascertained that Adam owns no books. In SQL, null is a marker, not a value.

  8. Minifloat - Wikipedia

    en.wikipedia.org/wiki/Minifloat

    A minifloat in 1 byte (8 bit) with 1 sign bit, 4 exponent bits and 3 significand bits (in short, a 1.4.3 minifloat) is demonstrated here. The exponent bias is defined as 7 to center the values around 1 to match other IEEE 754 floats [3] [4] so (for most values) the actual multiplier for exponent x is 2 x−7. All IEEE 754 principles should be ...

  9. IEEE 754 - Wikipedia

    en.wikipedia.org/wiki/IEEE_754

    The numerical value of such a finite number is (−1) s × c × b q. [a] Moreover, there are two zero values, called signed zeros: the sign bit specifies whether a zero is +0 (positive zero) or −0 (negative zero). Two infinities: +∞ and −∞. Two kinds of NaN (not-a-number): a quiet NaN (qNaN) and a signaling NaN (sNaN).