numpysavetxt

Numpysavetxt is a function in the NumPy library that writes array data to a text file. It is primarily used for exporting numeric data in a human-readable form and can handle 1-D and 2-D arrays. When saving a 2-D array, each row becomes a line in the output file with elements separated by a specified delimiter. For 1-D arrays, the default behavior is to write one value per line (a single column).

The function signature is numpy.savetxt(fname, X, fmt='%.18e', delimiter=' ', newline='\n', header='', footer='', comments='# ', encoding=None). The fname parameter can be a string path or a file-like object with a write method. X is the array to save. The fmt parameter controls numeric formatting and can be a single format string or a sequence of formats with one entry per column. The delimiter parameter specifies the string used to separate columns, with the default being a space; common alternatives include comma for CSV files. The header and footer parameters allow optional text to be written at the top or bottom of the file, and the comments parameter prefixes header lines (and can influence how lines starting with the comment prefix are treated). The encoding parameter selects text encoding when writing to a file.

Numpysavetxt is best used for interoperating with other text-based tools or for simple data inspection. It is not intended for high-performance storage or complex data types; for binary storage, other NumPy APIs such as save or savez are preferred. The typical workflow pairs savetxt with loadtxt for round-trip data exchange.