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Data cleansing or data cleaning is the process of identifying and correcting (or removing) corrupt, inaccurate, or irrelevant records from a dataset, table, or database.It involves detecting incomplete, incorrect, or inaccurate parts of the data and then replacing, modifying, or deleting the affected data. [1]
In a database, a table is a collection of related data organized in table format; consisting of columns and rows.. In relational databases, and flat file databases, a table is a set of data elements (values) using a model of vertical columns (identifiable by name) and horizontal rows, the cell being the unit where a row and column intersect. [1]
Even though the row is indicated by the first index and the column by the second index, no grouping order between the dimensions is implied by this. The choice of how to group and order the indices, either by row-major or column-major methods, is thus a matter of convention. The same terminology can be applied to even higher dimensional arrays.
Once processed and organized, the data may be incomplete, contain duplicates, or contain errors. [21] [22] The need for data cleaning will arise from problems in the way that the datum are entered and stored. [21] Data cleaning is the process of preventing and correcting these errors.
A record, especially in the context of row-based storage, may include key fields that allow indexing the records of a collection. A primary key is unique throughout all stored records; only one of this key exists. [15] In other words, no duplicate may exist for any primary key.
Most pages in this structure will be leaf pages which refer to specific table rows. Because each node (or internal page) can have more than two children, a B-tree index will usually have a shorter height (the distance from the root to the farthest leaf) than a Binary Search Tree.
Create duplicates for every edge to create an Eulerian graph. Find an Eulerian tour for this graph. Convert to TSP: if a city is visited twice, then create a shortcut from the city before this in the tour to the one after this. To improve the lower bound, a better way of creating an Eulerian graph is needed.
CSV is a delimited text file that uses a comma to separate values (many implementations of CSV import/export tools allow other separators to be used; for example, the use of a "Sep=^" row as the first row in the *.csv file will cause Excel to open the file expecting caret "^" to be the separator instead of comma ","). Simple CSV implementations ...