readtable — Import tabular text or spreadsheet data into a table.
readtable(filename, ...) imports delimited text or spreadsheet data into a table using name-value controls or an import-options structure.
Syntax
T = readtable(filename)
T = readtable(filename, nameValuePairs...)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
filename | StringScalar | Yes | — | Text or spreadsheet file path. |
nameValuePairs | Any | Variadic | — | Name-value import options. |
Returns
| Name | Type | Description |
|---|---|---|
out | Any | Result value. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:table:InvalidArgument | Arguments or table metadata are invalid. | table: invalid argument |
RunMat:table:InvalidIndex | Table indexing is invalid. | table: invalid index |
RunMat:table:InvalidVariable | A table variable name or value is invalid. | table: invalid variable |
RunMat:readtable:IOError | readtable cannot open or read the requested file. | readtable: file read failed |
RunMat:readtable:UnsupportedFileType | readtable receives a file type outside the text or spreadsheet import backends. | readtable: unsupported file type |
How readtable works
- Supports inferred or explicit variable names, missing tokens, text type, row names, sheet and range selection, and import-options structures created by
detectImportOptionsorspreadsheetImportOptions. - Documented integer
VariableTypespreserve all eight native classes. Decimal fields are parsed directly into the requested integer class, including exactint64anduint64values aboveflintmax, with class-specific saturation for out-of-range values. - The documented
VariableNamesLinestructural control accepts all eight integer classes and is bounds-checked exactly. - Typed-integer values for implemented controls whose public datatype table excludes native integers are RunMat-only extensions. MATLAB compatibility mode rejects those forms before gathering or opening the file; ordinary residency still gathers transparently for host import.
- Imported table variables retain their double, single, integer, logical, text, datetime, or duration classes and values.
Examples
Import exact unsigned 64-bit values
opts = spreadsheetImportOptions('NumVariables', 1);
opts.VariableNames = {'Counter'};
opts.VariableTypes = {'uint64'};
T = readtable('counters.xlsx', opts)Expected output:
% T.Counter is a native uint64 table variable.Select the variable-name line with a native integer
T = readtable('report.csv', 'VariableNamesLine', uint8(2))Expected output:
% The second input line supplies table variable names.Using readtable with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how readtable changes the result.
Run a small readtable example, explain the result, then change one input and compare the output.
Related Io functions
Tabular
arrayDatastore · csvread · csvwrite · detectImportOptions · dlmread · dlmwrite · fileDatastore · parquetDatastore · parquetinfo · parquetread · readcell · readmatrix · 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 readtable is executed, line by line, in Rust.
- View the source for readtable 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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