查看String - String()的源代码

:[[String - object|String]]

{| border="0" cellpadding="20" width="100%"
|-
|width="100%" valign="top" align="left"|
<font color="olivedrab" size="+3">'''String()'''</font>


<font color="orange" size="+1">'''描述'''</font>

Constructs an instance of the String class. There are multiple versions that construct Strings from different data types (i.e. format them as sequences of characters), including: 

 -  a constant string of characters, in double quotes (i.e. a char array)
 -  a single constant character, in single quotes
 -  another instance of the String object
 -  a constant integer or long integer
 -  a constant integer or long integer, using a specified base
 -  an integer or long integer variable
 -  an integer or long integer variable, using a specified base
 -  a float or double, using a specified decimal palces 

Constructing a String from a number results in a string that contains the ASCII representation of that number. The default is base ten, so 
<pre style="color:dimgray">
String thisString = String(13);
</pre>

gives you the String "13". You can use other bases, however. For example, 

<pre style="color:dimgray">
String thisString = String(13, HEX);
</pre>

gives you the String "D", which is the hexadecimal representation of the decimal value 13. Or if you prefer binary, 

<pre style="color:dimgray">
String thisString = String(13, BIN);
</pre>

gives you the String "1101", which is the binary representation of 13. 



<font color="orange" size="+1">'''语法'''</font>

String(val)
String(val, base)
String(val, decimalPlaces) 


<font color="orange" size="+1">'''参数'''</font>

val: a variable to format as a String - string, char, byte, int, long, unsigned int, unsigned long, float, double
base (optional) - the base in which to format an integral value
decimalPlaces (only if val is float or double) - the desired decimal places 


<font color="orange" size="+1">'''返回值'''</font>

an instance of the String class 


<font color="orange" size="+1">'''示例'''</font>

All of the following are valid declarations for Strings. 

<pre style="color:dimgray">
String stringOne = "Hello String";                                     // using a constant String
String stringOne =  String('a');                                          // converting a constant char into a String
String stringTwo =  String("This is a string");                 // converting a constant string into a String object
String stringOne =  String(stringTwo + " with more"); // concatenating two strings
String stringOne =  String(13);                                          // using a constant integer
String stringOne =  String(analogRead(0), DEC);          // using an int and a base
String stringOne =  String(45, HEX);                                // using an int and a base (hexadecimal)
String stringOne =  String(255, BIN);                               // using an int and a base (binary)
String stringOne =  String(millis(), DEC);                        // using a long and a base
String stringOne =  String(5.698, 3);                                // using a float and the decimal places
</pre>

|}

----

[[String - object|返回String]]

[[Arduino语法参考 | 返回Arduino语法参考列表]]

更多建议和问题欢迎反馈至 [http://www.yfrobot.com YFRobot论坛]