`detectImportOptions`

Guesses how to read a data file and returns import options.

Category: Language Fundamentals > Data Types

Syntax

opts = detectImportOptions(filename)

Inspects the file and returns an options object.

Description

The function reads the start of the file and decides the delimiter, whether the first line holds variable names, and a type for each column (numbers become double, text becomes char). You can edit the properties, for example change a type or select some variables, and then pass the object to readtable or readmatrix.

This lets you adjust the reading without writing the options by hand.

Input arguments

filename: Path of a delimited text file such as .csv.

Output arguments

opts: Options object with properties such as Delimiter, VariableNames, VariableTypes and DataLines.

Example

Detect and read

fid = fopen('demo.csv', 'w');
fprintf(fid, 'a,b\n1,x\n2,y\n');
fclose(fid);
opts = detectImportOptions('demo.csv');
opts.VariableNames
opts.VariableTypes
T = readtable('demo.csv', opts)

Output

ans = 1×2 cell

    {'a'}    {'b'}
ans = 1×2 cell

    {'double'}    {'char'}
T = 2×2 table

    a      b  
    _    _____

    1    {'x'}
    2    {'y'}

The example first writes a small file in the current folder.

detectImportOptions