我有以下任務(wù)我成功了，但是代碼效率很低，如果有人能告訴我一種更有效的方法，也許是子字符串，我將不勝感激。那作業(yè)：/** * Separates a given string into tokens, which are the "words" that are * separated by one or more occurrences of the given separator character. * Returns the tokens as an array of String values. */public static String[] tokenize (String str, char separator) { // Removes all the occurrences of the separator at the beginning and end of str String source = trim(str, separator); String[] tokens = new String[charRunCount (source,separator)+1]; String tmp = ""; // a string in order to take a word, then run over this string int j = 0; int i = 0; while (i < tokens.length) { if ( source.charAt (j) != separator ) { do { tmp += source.charAt (j); if ( j >= source.length () - 1 ) { break; } else { // so that we math the source length j++; } } while (source.charAt (j) != separator); } if ( source.charAt (j) == separator ) { j++; while (source.charAt (j) == separator) { j++; } } tokens[i] = tmp;// taking the token into place tmp = ""; //resetting the token so we can begin anew i++; } return tokens;}cahrRunCount 函數(shù)： public static int charRunCount(String str, char c){ char last = 0; int counter = 0; for (int i = 0; i < str.length(); i++) { // whenever a run starts. if (last != c && str.charAt(i) == c) { counter++; } last = str.charAt(i); } return counter;}我不能使用 import 或 regex，謝謝！
2 回答
慕妹3146593
TA貢獻1820條經(jīng)驗 獲得超9個贊
使用 String.split 方法
String[] tokens = str.split(separator)
for(String token:tokens){
//your code goes here
}
文檔在這里
https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#split(java.lang.String)
猛跑小豬
TA貢獻1858條經(jīng)驗 獲得超8個贊
如果需要，您可以使用 String 類的 split 方法（就像@Amidala Siva Kumar 建議的那樣），如下所示：
public static String[] tokenize (String str, char separator) {
String[] tokens = str.split(separator);
return tokens;
}
或者，如果您想使用自己的拆分來執(zhí)行此操作，則可以這樣做（對代碼的改進）。
public static String[] tokenize (String str, char separator) {
String sep = ""+separator;
int max_size = str.length() - str.replace(sep, "").length() +1 ; // Calculate max array size
String[] temp = new String[max_size];
int start = 0, index = 0, exact_size = 0;
int pos = str.indexOf(separator);
while (pos>=start) {
if (pos>start){
temp[index++] = str.substring(start,pos).trim();
exact_size++;
}
start = pos + 1;
pos = str.indexOf(separator,start);
}
String[] tokens = new String[exact_size];
System.arraycopy(temp, 0, tokens, 0, exact_size);
return tokens;
}
希望你覺得它有用。
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