MATLAB Reading Excel Data from TXT Files: A Bridge for Data Interchange, Efficiently Loading Excel Files

# 1. Introduction to MATLAB Reading Data from TXT Files

MATLAB is a powerful technical computing software that offers a rich set of tools and functions for data processing and analysis. In many real-world applications, data is often stored in text files (TXT). MATLAB provides multiple methods to read and process TXT files, enabling us to efficiently extract, process, and analyze data.

This guide will introduce an overview of MATLAB's approach to reading TXT files, including parsing TXT file formats, techniques for data reading and processing, methods for data visualization and analysis, and examples of MATLAB applications in practice. With this guide, readers will master the skills needed to read and process TXT files in MATLAB and be able to apply them to various data analysis tasks.

# 2. Parsing TXT File Formats

### 2.1 TXT File Structure and Data Types

TXT (text files) are simple text format files typically used to store plain text data. Their structure generally includes:

- **File Header:** Contains file information such as creation date, modification date, etc.
- **Body:** Contains the actual text data, usually line-separated.
- **File Footer:** Often empty but may contain some metadata.

The data types in TXT files are usually strings, but they can also contain other types of data such as numbers, dates, etc.

### 2.2 Data Preprocessing and Formatting

Before reading TXT files, some data preprocessing and formatting operations may be required to ensure that the data can be correctly parsed by MATLAB. These operations include:

- **Removing Excess Whitespace:** TXT files may contain extra whitespace characters such as spaces and tabs, which need to be removed.
- **Uniform Line Breaks:** Different operating systems use different line break characters (Windows uses "\r\n", Unix uses "\n"), which need to be unified to the line break character supported by MATLAB.
- **Converting Data Types:** If the TXT file contains non-string data, it needs to be converted to data types supported by MATLAB, such as numbers, dates, etc.

The following code example shows how to preprocess and format TXT file data:

% Read TXT file
data = fileread('data.txt');

% Remove excess whitespace
data = strrep(data, ' ', '');
data = strrep(data, '\t', '');

% Uniform line breaks
data = strrep(data, '\r\n', '\n');

% Convert data types
data_num = str2num(data);

### 2.2.1 Common TXT File Formats

TXT files can adopt different formats; common formats include:

- **Delimiter-separated:** Data items are separated by delimiters (such as commas, semicolons, spaces, etc.).
- **Fixed Width:** Each data item occupies a fixed width, usually padded with spaces.
- **Free Format:** There are no clear delimiters between data items; parsing is required based on context.

### 2.2.2 Data Formatting Examples

**Delimiter-separated:**

name,age,gender
John,30,male
Mary,25,female

**Fixed Width:**

John     30 male
Mary     25 female

**Free Format:**

John is 30 years old and male.
Mary is 25 years old and female.

# 3. MATLAB Data Reading and Processing

### 3.1 File Reading and Data Extraction

#### 3.1.1 File Reading

MATLAB offers various file reading functions, commonly including:

- `fopen`: Opens a file and returns a file identifier.
- `fscanf`: Reads formatted data from a fi