Word Cloud (词云)

今天要总结的是 Word Cloud 最后一个部分了，用 Matlab 来创建 word cloud。Matlab R2018b 已经提供 [wordcloud](https://www.mathworks.com/help/matlab/ref/wordcloud.html) 函数可以直接生成词云了。
##### >> Create Word Cloud via Matlab

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1. 准备文本。

不多说了，懒人继续用上次那个 Word Cloud History.txt 的文本吧。

2. 读取并清洗数据文本。

%read txt as a string
text = string(fileread('C:UsersyukiDesktopWordCloudHistory.txt'));
%delete puchuation
punctuationCharacters = ["." "?" "!" "," ";" ":"];
text = replace(text,punctuationCharacters," ");
%convert a string to array
words = split(join(text));
%delete the words has less than 5 characters, which are problely stop words
words(strlength(words)<5) = [];
%change all words to lowercase
words = lower(words);

3. 计算词频并生成数组。

%calculate the frequencies for every word
[numOccurrences,uniqueWords] = histcounts(categorical(words));

4. 生成 word cloud。

figure
%set properties for word cloud
wordcloud(uniqueWords,numOccurrences,'Shape', "rectangle", 'MaxDisplayWords', 200);
title("Word Cloud History")

##### >> Notes

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1. Matlab 也有插件可以直接生成词云，操作简单，不用编程，哈哈。

2. 既然已经说了各种可以创建词云的方法，那么就顺便总结一下什么方法好用方便不花钱。

Tool		Easy Use		Free		Need Script
Python		Clear document, powerful text mining library		Yes		Yes
JavaScript		Need to extract array by own, and need to find a way to save the image		Yes		Yes
R		Clear document, powerful text mining library		Yes		Yes
Matlab		Clear document, interactive interface		No		Optional

##### >> Sample Code

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download here

##### >> Related Blogs

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1. [Word Cloud (词云) - Python](https://www.cnblogs.com/yukiwu/p/10967037.html) 2. [Word Cloud (词云) - JavaScript](https://www.cnblogs.com/yukiwu/p/10968816.html) 3. [Word Cloud (词云) - R](https://www.cnblogs.com/yukiwu/p/10969250.html)