Strings

name: portada
class: portada-slide, center, middle

# Strings

.footnote[Joan Puigcerver Ibáñez]

---
layout: true
class: regular-slide
.right[.logo[![logoMislata](/itb/images/logo_mislata.png)]]

---
# String
- Un String és un array no modificable de chars.
- Podem accedir a un char en la posició
  - char charAt(int i);
- I llargada
  - int length();

```
String someString = "My String";
char someChar = someString.charAt(0);

int length = someString.length();
```

---
# String - JavaDoc
- Javadoc: documentació d'una classe

https://docs.oracle.com/javase/8/docs/api/java/lang/String.html

---
# Altres mètode de String
- int compareTo(String anotherString)
- int   compareToIgnoreCase(String str)
- boolean   endsWith(String suffix)
- boolean   equals(Object anObject)
- boolean   equalsIgnoreCase(String anotherString)
- ...

???
- int   indexOf(String str)
    Returns the index within this string of the first occurrence of the specified substring.
- boolean   isEmpty()
    Returns true if, and only if, length() is 0.
- boolean   startsWith(String prefix)
    Tests if this string starts with the specified prefix.
- String  substring(int beginIndex)
    Returns a string that is a substring of this string.
- String  substring(int beginIndex, int endIndex)
    Returns a string that is a substring of this string.
- String  trim()
    Returns a string whose value is this string, with any leading and trailing whitespace removed.

---
# String format
- static String format(String format, Object... args)
  - Returns a formatted string using the specified format string and arguments.
- Tenim l'equivalent per printar per pantalla
  - System.out.printf

```
// Joe has 35 years
String output = String.format("%s has %d years", "Joe", 35);

System.out.printf("%s has %d years", "Joe", 35);
```

---
# String format
### Variables

<table>
<tr><td>%c</td><td> - character</td></tr>
<tr><td>%d</td><td> - integer</td></tr>
<tr><td>%f</td><td> - floating point  decimal number</td></tr>
<tr><td>%s</td><td> - any type  String value</td></tr>
</table>

### Especial
<table>
<tr><td>%n</td><td> - new line</td></tr>
</table>

---
# String format - print integers

```
// Default formatting:
String.format("%d", 93); 
// prints 93

// Specifying a width:
String.format("|%20d|", 93); 
// prints: |                  93|

// Left-justifying within the specified width:
String.format("|%-20d|", 93); 
// prints: |93                  |

// Pad with zeros:
String.format("|%020d|", 93); 
// prints: |00000000000000000093|
```

---
# String format - print double

```
System.out.printf("rounded double: %.3f", 7.548746484);
// rounded double: 7.549
```

---
# String format
- https://dzone.com/articles/java-string-format-examples
- https://docs.oracle.com/javase/tutorial/java/data/numberformat.html