arduino的String類
阿新 • • 發佈：2019-01-31
String類主要的就是一些字串處理函式，比string具有更多更輕大的功能，so用起來很爽！
下面是其主要函式介紹，用例主要參考官方資料。
1、定義，這個就不多說了
2、字串的連線與追加，官方將兩種功能分開了，其實覺得和在一起對比理解會更好一點String stringOne = "Hello String"; String stringOne = String('a'); String stringTwo = String("This is a string"); String stringOne = String(stringTwo + " with more"); String stringOne = String(13); String stringOne = String(analogRead(0), DEC); String stringOne = String(45, HEX); String stringOne = String(255, BIN); String stringOne = String(millis(), DEC);
stringThree = stringOne + 123;
stringThree = stringOne + 123456789;
stringThree = stringOne + 'A';
stringThree = stringOne + "abc";
stringThree = stringOne + stringTwo;
stringOne += 123456789;
等同於
stringTwo.concat(123456789);indexOf('?')：從字串頭部開始查詢
lastindexOf('?')：從尾部開始查詢
4、length():字串長度測量函式，返回值為字串的長度int firstClosingBracket = stringOne.indexOf('>'); 預設是從頭部開始查詢，還可以指定開始位置 int secondOpeningBracket = firstClosingBracket + 1; int secondClosingBracket = stringOne.indexOf('>', secondOpeningBracket ); lastindexOf()的用法類似 int lastParagraph = stringOne.lastIndexOf("<p"); int secondLastGraf = stringOne.lastIndexOf("<p", lastParagraph - 1);
String txtMsg = "This is a test!";
int lastStringLength = txtMsg.length();5、trim():將字串中的字串去除，包括空格、回車、Tab等
String str = "this is a
test ,do you kown?";
stringOne.trim();大轉小：toLowerCase()
小轉大：toUpperCase()
7、替換：用後面的字串替換前面的字串
String stringOne = "<html><head><body>";
stringTwo.replace("<", "</");改變字串給定位置的字元：setcharAt，無返回值。
String reportString = "SensorReading: 456";
char mostSignificantDigit = reportString.charAt(15);
reportString.setCharAt(13, '=');String stringOne = "HTTP/1.1 200 OK";
if (stringOne.startsWith("HTTP/1.1")) {
Serial.println("Server's using http version 1.1");
}
if (stringOne.startsWith("200 OK", 9)) {
Serial.println("Got an OK from the server");
}11、字串轉換為整型：toInt(),返回值為轉換後的整型值。
12、字串解析函式：substring(?,...),返回值為指定位置的字串值
String stringOne = "Content-Type: text/html";
if (stringOne.substring(19) == "html") {
Serial.println("It's an html file");
}
if (stringOne.substring(14,18) == "text") {
Serial.println("It's a text-based file");
}