Data Import and Visualization Flashcards

Which MATLAB function reads a JSON file and converts it to a MATLAB structure?

Answer: jsondecode(fileread('data.json'))

MATLAB has no single jsonread function; the standard pattern is fileread() to get the raw text then jsondecode() to parse it into a struct.

What does 'subplot(2,2,3)' specify in MATLAB?

Answer: The axes in the bottom-left position of a 2x2 grid

subplot(m,n,p) selects axes number p in an m-by-n grid; positions are numbered left-to-right, top-to-bottom, so position 3 is bottom-left in a 2x2 grid.

What is the purpose of 'detectImportOptions' in MATLAB?

Answer: Automatically detects and returns configurable import options for a file

detectImportOptions inspects a file and returns an ImportOptions object pre-configured for that file, which you can then modify before passing to readtable or readmatrix.

Which property of a MATLAB line object controls the thickness of the plotted line?

Answer: LineWidth

The LineWidth property (in points) controls the rendered thickness of line and marker edge strokes on a MATLAB plot object.

What does 'yyaxis right' do in MATLAB?

Answer: Activates the right y-axis so subsequent plot commands use it

yyaxis right switches the active y-axis to the right side; subsequent plot commands will be associated with the right y-axis scale.

When would you use 'readlines' instead of 'readtable' in MATLAB?

Answer: When reading a plain text file as an array of string lines without parsing structure

readlines reads a text file and returns each line as a string in a string array, useful for unstructured text, logs, or files you intend to parse manually.

Which MATLAB function converts a datetime array to a numeric format suitable for plot axis ticks?

Answer: datenum

datenum converts a datetime or date string to a serial date number (days since Jan 0, 0000), which MATLAB's older plotting functions use for date-based axes.