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Pandas is built around data structures called Series and DataFrames. Data for these collections can be imported from various file formats such as comma-separated values, JSON, Parquet, SQL database tables or queries, and Microsoft Excel. [8] A Series is a 1-dimensional data structure built on top of NumPy's array.
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 ...
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 ...
Many statistical and data processing systems have functions to convert between these two presentations, for instance the R programming language has several packages such as the tidyr package. The pandas package in Python implements this operation as "melt" function which converts a wide table to a narrow one. The process of converting a narrow ...
A relational database (RDB [1]) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. [2]A database management system used to maintain relational databases is a relational database management system (RDBMS).
A flat-file database is a database stored in a file called a flat file. Records follow a uniform format, and there are no structures for indexing or recognizing relationships between records. The file is simple. A flat file can be a plain text file (e.g. csv, txt or tsv), or a binary file. Relationships can be inferred from the data in the ...
Its copy-on-write approach never overwrites currently-in-use data. Avoiding overwrites means the structure on disk/storage is always valid, so application or system crashes can never leave the database in a corrupted state. In its default mode, at worst, a crash can lose data from the last not-yet-committed write transaction.
SDF is one of a family of chemical-data file formats developed by MDL; it is intended especially for structural information. "SDF" stands for structure-data format, and SDF files actually wrap the molfile (MDL Molfile) format. Multiple records are delimited by lines consisting of four dollar signs ($$$$). A key feature of this format is its ...