I put a number in EditText line and it counts a double value in another.
But the double value of 4.8 should be 9.6 and not 9.6000000381469727.
I know it is normal for float but I would like to cut the amount of decimal numbers to 4. I'm not sure how to do this in my code.
private void calc(double number, operation input) {
double a = 0;
switch (input) {
case a:
valuedouble.setText(valuecount(number));
private String valueucount(double input) {
return Double.toString( input*2 );
}
Thanks for reply.
You can use the following command (format strings)
String.format("%.4f", number);
See this site for a complete list of format strings.
Related
i am trying to set maximum length in string value and put '..' instead of removed chrs like following
String myValue = 'Welcome'
now i need the maximum length is 4 so output like following
'welc..'
how can i handle this ? thanks
The short and incorrect version is:
String abbrevBad(String input, int maxlength) {
if (input.length <= maxLength) return input;
return input.substring(0, maxLength - 2) + "..";
}
(Using .. is not the typographical way to mark an elision. That takes ..., the "ellipsis" symbol.)
A more internationally aware version would count grapheme clusters instead of code units, so it handles complex characters and emojis as a single character, and doesn't break in the middle of one. Might also use the proper ellipsis character.
String abbreviate(String input, int maxLength) {
var it = input.characters.iterator;
for (var i = 0; i <= maxLength; i++) {
if (!it.expandNext()) return input;
}
it.dropLast(2);
return "${it.current}\u2026";
}
That also works for characters which are not single code units:
void main() {
print(abbreviate("argelbargle", 7)); // argelb…
print(abbreviate("🇩🇰🇩🇰🇩🇰🇩🇰🇩🇰", 4)); // 🇩🇰🇩🇰🇩🇰…
}
(If you want to use ... instead of …, just change .dropLast(2) to .dropLast(4) and "…" to "...".)
You need to use RichText and you need to specify the overflow type, just like this:
Flexible(
child: RichText("Very, very, very looong text",
overflow: TextOverflow.ellipsis,
),
);
If the Text widget overflows, some points (...) will appears.
I am looking for a way to get a String between 2 Strings using Arduino. This is the source String:
Hello, my name is John Doe# and my favourite number is 32#.
The output has to be:
String name = "John Doe"; //Between "name is " and "#"
String favouriteNumber = "32"; //Between "number is " and "#"
How can this be achieved with Arduino?
I am not able to find any information online about this. Those examples for C are not working anyway. I understand that using String is not recommended in Arduino, but I have to do it this way to make things simpler.
By the way, this method of using a '#' to indicate the end of the data is not an ideal way to do it as I would like the input to be more human readable and more natural. Would anyone please suggest another way to do this as well?
Thanks in advance!
Function midString find the substring that is between two other strings "start" and "finish". If such a string does not exist, it returns "". A test code is included too.
void setup() {
test();
}
void loop() {
delay(100);
}
String midString(String str, String start, String finish){
int locStart = str.indexOf(start);
if (locStart==-1) return "";
locStart += start.length();
int locFinish = str.indexOf(finish, locStart);
if (locFinish==-1) return "";
return str.substring(locStart, locFinish);
}
void test(){
Serial.begin(115200);
String str = "Get a substring of a String. The starting index is inclusive (the corresponding character is included in the substring), but the optional ending index is exclusive";
Serial.print(">");
Serial.print( midString( str, "substring", "String" ) );
Serial.println("<");
Serial.print(">");
Serial.print( midString( str, "substring", "." ) );
Serial.println("<");
Serial.print(">");
Serial.print( midString( str, "corresponding", "inclusive" ) );
Serial.println("<");
Serial.print(">");
Serial.print( midString( str, "object", "inclusive" ) );
Serial.println("<");
}
just searched for this and saw no answer so i cooked one up.
i prefer working with String as well because of code readability and simplicity.
for me its more important than squeezing every last drop of juice out of my arduino.
String name = GetStringBetweenStrings("Hello, my name is John Doe# and my favourite number is 32#." ,"name is ","#");
String GetStringBetweenStrings(String input, String firstdel, String enddel){
int posfrom = input.indexOf(firstdel) + firstdel.length();
int posto = input.indexOf(enddel);
return input.substring(posfrom, posto);
}
watch out for the first case its fine, but for the second one you would have to change the second filter sting to "#." so it doesn't use the first occurrence of the #
How to Convert a string in float up to 3 decimal places in Arduino?
My string is
23.455 but when I convert it into float by toFloat() method it gives 23.45 and removes last digit.
void setup ()
{
Serial.begin (115200);
float f = atof ("23.455"); // convert to float
Serial.println (f, 3); // print with 3 decimal places
} // end of setup
void loop ()
{
} // end of loop
Output:
23.455
I found that.. float holds the whole value up to 3 decimal places but it just print up to 2 decimal places so the float value can be use for calculation
This may be useful. ArduinoFloatToString
I want to limit the no. of character that can be put on JTextField because on my database I have this column that has Sex,Status (which the no. of char. allowed is 1 only).
and Middle Initial (which the no. of char. allowed is 2 only).
This what I have in my mind :
(for Sex,Status column)
String text = jTextField2.getText();
int count = text.();
if (count>1) {
(delete the next character that will be input)
}
(for M.I. column)
String text = jTextField1.getText();
int count = text.();
if (count>2) {
(delete the next character that will be input)
}
is this possible? is there a command that will delete the next character, so the no. of char. is acceptable for my database?
Sure. Just use String#substring.
String middleInitial = "JKL";
middleInitial.substring(0, 2);
System.out.println(middleInitial); // => JK
Similarly, you can use substring(0, 1) for sex.
It might be better if sex is an enum, though.
public enum Sex {
MALE("m"), FEMALE("f");
final String symbol;
private Sex(String symbol) {
this.symbol = symbol;
}
}
Now you can use it like this:
String sex = "male";
Sex.valueOf(sex.toUpperCase());
Or directly
Sex.MALE;
Instead of a text field for sex, you might use a JComboBox so the user can only choose one of the two options. This way you're sure to have valid input.
I want to convert a String to an int, and all I could find is that you have to convert the String to a char array and then cast this array to an int, but my code produces strange values and I can't figure out what the problem is.
void ledDimm(String command)
{
// Get the Value xx from string LEDDimm=xx
String substring = command.substring(8, command.length());
Serial.println("SubString:");
Serial.println(substring);
Serial.println("SubString Length:");
Serial.println(substring.length());
// Create a Char Array to Store the Substring for conversion
char valueArray[substring.length() + 1];
Serial.println("sizeof ValueArray");
Serial.println(sizeof(valueArray));
// Copy the substring into the array
substring.toCharArray(valueArray, sizeof(valueArray));
Serial.println("valueArray:");
Serial.println(valueArray);
// Convert char array to an int value
int value = int(valueArray);
Serial.println("Integer Value:");
Serial.println(value);
// Write the Value to the LEDPin
analogWrite(LEDPin, value);
}
And the serial output looks like this:
Received packet of size 11
From 192.168.1.4, port 58615
Contents:
LEDDimm=100
SubString:
100
SubString Length:
3
sizeof ValueArray
4
valueArray:
100
Integer Value:
2225
I expected to get an int with the value of 100 but the actual int is 2225?! What have I done wrong here?
There is even an (undocumented) toInt() method in the String class:
int myInt = myString.toInt();
You need to use the function int value = atoi(valueArray); where valueArray is a null terminated string.
The toInt () method is very useful in this aspect, but I found that it is able to convert only strings of length five or less, especially a value less than 65535 as its the maximum value int can take. Over this value, it just gives random numbers (overflowing values). Please be aware of this when you use this method as it killed a lot of my useful time to figure this out. Hope it helps.