rainfall_my.java

public static double mean(String town, String strng) {
	String[] dataList = strng.split("\n");
	String targetData = null;
	String targetRainfall = null;
	double sum = 0;
	
	for(String data : dataList){
		if(town.equals(data.split(":")[0])){
			targetData = town;
			targetRainfall = data.split(":")[1];
		}
	}
	
	if(targetData == null){
		return -1;
	}
	
	String[] rainfalls = targetRainfall.split(",");
	for(String rainfall : rainfalls){
		sum += Double.parseDouble(rainfall.split(" ")[1]);
	}
	
       return sum / 12;
}
public static double variance(String town, String strng) {
   	double average = mean(town, strng);
   	String[] dataList = strng.split("\n");
	String targetData = null;
	String targetRainfall = null;
	double sum = 0;
	
	for(String data : dataList){
		if(town.equals(data.split(":")[0])){
			targetData = town;
			targetRainfall = data.split(":")[1];
		}
	}
	
	if(targetData == null){
		return -1;
	}
	
	String[] rainfalls = targetRainfall.split(",");
	for(String rainfall : rainfalls){
		sum += Math.pow(Double.parseDouble(rainfall.split(" ")[1]) - average, 2);
	}
   	
   	return sum / 12;
}