[英]Transposing arrays
I am using the following code to read in a CSV file: 我使用以下代码读取CSV文件:
String next[] = {};
List<String[]> dataArray = new ArrayList<String[]>();
try {
CSVReader reader = new CSVReader(new InputStreamReader(getAssets().open("inputFile.csv")));
for(;;) {
next = reader.readNext();
if(next != null) {
dataArray.add(next);
} else {
break;
}
}
} catch (IOException e) {
e.printStackTrace();
}
This turns a CSV file into the array 'dataArray'. 这会将CSV文件转换为数组'dataArray'。 My application is for a dictionary type app - the input data's first column is a list of words, and the second column is the definitions of those words.
我的应用程序是一个字典类型的应用程序 - 输入数据的第一列是单词列表,第二列是这些单词的定义。 Here is an example of the array loaded in:
以下是加载的数组的示例:
Term 1, Definition 1
Term 2, Definition 2
Term 3, Definition 3
In order to access one of the strings in the array, I use the following code: 为了访问数组中的一个字符串,我使用以下代码:
dataArray.get(rowNumber)[columnNumber]
However, I need to be able to generate a list of all the terms, so that they can be displayed for the dictionary application. 但是,我需要能够生成所有术语的列表,以便可以为词典应用程序显示它们。 As I understand it, accessing the columns by themselves is a much more lengthy process than accessing the rows (I come from a MATLAB background, where this would be simple).
据我所知,访问列是一个比访问行更长的过程(我来自MATLAB背景,这将是简单的)。
It seems that in order to have ready access to any row of my input data, I would be better off transposing the data and reading it in that way; 似乎为了能够随时访问输入数据的任何行,我最好转置数据并以这种方式读取数据; ie:
即:
Term 1, Term 2, Term3
Definition 1, Definition 2, Definition 3
Of course, I could just provide a CSV file that is transposed in the first place - but Excel or OO Calc don't allow more than 256 rows, and my dictionary contains around 2000 terms. 当然,我可以提供一个首先转置的CSV文件 - 但Excel或OO Calc不允许超过256行,而我的词典包含大约2000个术语。
Any of the following solutions would be welcomed: 欢迎以下任何解决方案:
You would probably be better served by using a Map data structure (eg HashMap ): 使用Map数据结构(例如HashMap )可能会更好:
String next[] = {};
HashMap<String, String> dataMap = new HashMap<String, String>();
try {
CSVReader reader = new CSVReader(new InputStreamReader(getAssets().open("inputFile.csv")));
for(;;) {
next = reader.readNext();
if(next != null) {
dataMap.put(next[0], next[1]);
} else {
break;
}
}
} catch (IOException e) {
e.printStackTrace();
}
Then you can access the first column by 然后你可以访问第一列
dataMap.keySet();
and the second column by 和第二列
dataMap.values();
Note one assumption here: that the first column of your input data is all unique values (that is, there are not repeated values in the "Term" column). 请注意这里的一个假设:输入数据的第一列是所有唯一值(即“Term”列中没有重复的值)。
To be able to access the keys (terms) as an array, you can simply do as follows: 为了能够将键(术语)作为数组访问,您可以按如下方式执行:
String[] terms = new String[dataMap.keySet().size()];
terms = dataMap.keySet().toArray(terms);
If each row has two values, where the first one is the term and the second one is the definition, you could build a Map
of it like this (Btw, this while
loop does the exact same thing as your for
loop): 如果每一行都有两个值,第一个是术语,第二个是定义,你可以像这样构建一个
Map
(顺便说一句,这个while
循环与你的for
循环完全相同):
String next[] = {};
Map<String, String> dataMap = new HashMap<String, String>();
try {
CSVReader reader = new CSVReader(new InputStreamReader(getAssets().open("inputFile.csv")));
while((next = reader.readNext()) != null) {
dataMap.put(next[0], next[1]);
}
} catch (IOException e) {
e.printStackTrace();
}
Then you can get the definition from a term via: 然后,您可以通过以下方式从术语中获取定义:
String definition = dataMap.get(term);
or all definitions like this: 或所有这样的定义:
for (String term: dataMap.keySet()) {
String definition = dataMap.get(term);
}
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