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Data Preparation and Import

Loading a File

Click the Open File button on the launcher screen and select a file. To use sample data, choose from the "Sample Data" section on the launcher screen. See Getting Started for detailed steps.

Supported File Formats

MIDAS supports four file formats: CSV, TSV, MDS, and ZIP.

CSV (Comma-Separated Values) The most common data format. Columns are separated by commas (,). File extension is typically .csv.

TSV (Tab-Separated Values) A file format where columns are separated by tab characters. File extension is typically .tsv or .txt.

MDS (MIDAS Project File) MIDAS's native project file format. Contains datasets, analysis settings, and reports.

ZIP Archive files containing CSV or TSV files. Multiple files can be loaded at once.

Excel files (.xlsx) cannot be loaded directly. Save your spreadsheet as CSV from Excel's "Save As" menu.

Character Encoding UTF-8 encoding is supported. When saving CSV from Excel, select "CSV UTF-8 (Comma delimited)" format.

File Structure

MIDAS reads the first row as column names and subsequent rows as data.

  • Row 1: Column names (header row)
  • Row 2 onwards: Data rows

Example:

Name,Age,Country
Alice,25,USA
Bob,30,Japan
Charlie,28,UK

Data Types

MIDAS automatically determines data types when loading.

boolean Boolean values represented by true/false, 1/0, yes/no, y/n, etc.

int64 (integer) Numbers without decimal points (e.g., 1, 42, -10).

float64 (floating point) Numbers with decimal points (e.g., 3.14, 0.5, -2.71).

date Date data (e.g., 2025-11-17, 2025/11/17).

datetime Data including both date and time (e.g., 2025-11-17 14:30:00).

string Text data that does not match any of the above types.

enum Categorical data with a fixed set of values. Cannot be automatically inferred; you create them manually. First, create an Enum definition from Data > Enum Definitions, setting the values and their order. Then use Column Type Conversion to convert a string column to the Enum. Since value order can be defined, enum is suitable for ordinal scale data.

Data types are displayed in column headers as Age (int64). If a data type is not correctly determined, use Column Type Conversion to fix it. The original dataset is not modified; conversion results are created as a new dataset.

Measurement Scales

MIDAS automatically assigns a measurement scale (Nominal, Ordinal, Interval, Ratio) to each column. Measurement scales affect the available graph types and statistical methods. Right-click a column in the Data Table to change its scale.

See Data Types and Measurement Scales for what each scale means and how it affects analysis.

Next steps

See also