parquetread — Read Parquet columnar data into a table.
parquetread(filename) decodes a Parquet file with Arrow-backed Parquet support and returns a RunMat table. Common numeric, logical, string, date, and timestamp columns are mapped to table variables.
Syntax
parquetread(filename)How parquetread works
SelectedVariableNameslimits the imported variables, preserves the requested output order, and rejects unknown or duplicate names.RowGroupsaccepts one-based row-group indices and decodes only those groups.OutputTypeaccepts"table";"timetable"is rejected until timetable row-time synthesis for Parquet is implemented.RowFilteris rejected until rowfilter predicate execution is available.- Unsupported nested or complex Parquet logical types raise deterministic import errors instead of producing partial columns.
Examples
Read a Parquet file
T = parquetread("measurements.parquet")Expected output:
T = tableRead selected columns and row groups
T = parquetread("measurements.parquet", "SelectedVariableNames", ["time", "value"], "RowGroups", 2)Expected output:
T = tableUsing parquetread with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how parquetread changes the result.
Run a small parquetread example, explain the result, then change one input and compare the output.
FAQ
Does parquetread run on the GPU?⌄
No. Parquet is a compressed columnar file format, so decoding and table construction happen on the host.
Related Io functions
Tabular
arrayDatastore · csvread · csvwrite · detectImportOptions · dlmread · dlmwrite · fileDatastore · parquetDatastore · parquetinfo · readcell · readmatrix · readtable · readtimetable · spreadsheetImportOptions · writecell · writematrix · writetable · writetimetable · xlsread · xlswrite
Repl Fs
addpath · cd · copyfile · delete · dir · exist · fileattrib · fileparts · fullfile · genpath · getenv · getpref · isenv · isfile · isfolder · ispref · ls · matlabroot · memmapfile · mkdir · movefile · open · opentoline · path · pathsep · pcode · pwd · readstruct · rehash · restoredefaultpath · rmdir · rmpath · run · savepath · setenv · setpref · system · tempdir · tempname · uigetdir · uigetfile · uiputfile · unsetenv · userpath · what · winqueryreg · xmlread · xmlwrite
Filetext
fclose · feof · fgetl · fgets · fileread · filewrite · fopen · fprintf · fread · frewind · fwrite · readlines · writelines
Import
Json
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how parquetread is executed, line by line, in Rust.
- View the source for parquetread in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
About RunMat
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