parquetinfo — Inspect Parquet file schema and row-group metadata.
parquetinfo(filename) reads Parquet file metadata and returns a scalar struct containing filename, file size, row count, row-group count, variable count, variable names, variable physical types, writer version, creator string, row-group metadata, compression labels, and encoding labels.
Syntax
parquetinfo(filename)How parquetinfo works
- The file footer and schema are parsed with the same Arrow-backed Parquet reader used by
parquetread. - Row groups are reported as a struct with
RowGroup1,RowGroup2, and so on, each containing row count, total byte size, and column count. - Compression and encoding labels are reported from the first row group when row groups are present.
Example
Inspect Parquet metadata
info = parquetinfo("measurements.parquet")Expected output:
info = structUsing parquetinfo with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how parquetinfo changes the result.
Run a small parquetinfo example, explain the result, then change one input and compare the output.
FAQ
Does parquetinfo decode the whole file?⌄
No. It reads the Parquet metadata footer and schema, not the full data payload.
Related Io functions
Tabular
arrayDatastore · csvread · csvwrite · detectImportOptions · dlmread · dlmwrite · fileDatastore · parquetDatastore · parquetread · 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 parquetinfo is executed, line by line, in Rust.
- View the source for parquetinfo in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
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