row0

row0 is a term used to denote the first row in a two-dimensional data structure that uses zero-based indexing. In computer science, many programming languages and data libraries index rows starting at zero, so the initial row is labeled row0 and has index 0. This convention contrasts with one-based indexing used in some human-readable contexts, where the first row is called row 1.

In matrices and arrays, row0 corresponds to the set of elements with the first coordinate. Access patterns depend on the language: in a 2D array a, the first row is typically accessed as a[0] or a[0, :] depending on the syntax (for example, a[0] in Python lists, a[0, :] in NumPy). In row-major languages like C and C++, the elements of row0 are stored contiguously along the column axis, whereas in column-major languages like Fortran, the memory layout places a different emphasis on rows and columns.

In data processing, row0 is commonly used when iterating over rows: for i from 0 to n-1, process row i. In many data frames and tables, the internal representation follows zero-based indexing, so the physical first data row corresponds to index 0, even if user interfaces display row numbers starting at 1.

In databases and CSV files intended for everyday use, headers are often separate from data rows. The first data row might be referred to as row 1 in user documentation, while code that processes the file will typically use index 0 for that row.

Variations exist: some systems adopt one-based indexing for simplicity or readability, or allow configurable indexing schemes. The concept of row0 is most visible in programming tutorials and codebases that demonstrate zero-based indexing.