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As such, a DataFrame can be thought of as having two indices: one column-based and one row-based. Because column names are stored as an index, these are not required to be unique. [9]: 103–105 If data is a Series, then data['a'] returns all values with the index value of a.
the basic code for a table row; code for color, alignment, and sorting mode; fixed texts such as units; special formats for sorting; In such a case, it can be useful to create a template that produces the syntax for a table row, with the data as parameters. This can have many advantages: easily changing the order of columns, or removing a column
Most modern machines do renaming by RAM indexing a map table with the logical register number. E.g., P6 did this; future files do this, and have data storage in the same structure. However, earlier machines used content-addressable memory (CAM) in the renamer. E.g., the HPSM RAT, or Register Alias Table, essentially used a CAM on the logical ...
A pivot table is a table of values which are aggregations of groups of individual values from a more extensive table (such as from a database, spreadsheet, or business intelligence program) within one or more discrete categories. The aggregations or summaries of the groups of the individual terms might include sums, averages, counts, or other ...
The following is a list of Laplace transforms for many common functions of a single variable. [1] The Laplace transform is an integral transform that takes a function of a positive real variable t (often time) to a function of a complex variable s (complex angular frequency ).
Each entry on this list should be an article on its own (not merely a section in a less unusual article) and of decent quality, and in large meeting Wikipedia's manual of style. For unusual contributions that are of greater levity, see Wikipedia:Silly Things. In this list, a star indicates a featured article. A plus indicates a good article.
In relational algebra, a rename is a unary operation written as / where: R is a relation; a and b are attribute names; b is an attribute of R; The result is identical to R except that the b attribute in all tuples is renamed to a. [1]
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...