_evaluate

Char at position

Returns Char at the specified position

Char at position

Optionally Returns Char at the specified position

VOID is returned if specified position is out of String range

if(<name>.charAtOpt(2).take(_.isUpper)) ()
// is equivalent
if(<name>.length >=2 && <name>.charAt(2).isUpper) ()

Char index

Optionally returns index of the first Char passing the let function
```
    "abcd_abcd_".charIndexOpt(_ >= 'd', 4).tp // Prints: Opt(8)
    "abcd_abcd_".charIndexOpt('x' <> 'z') tp  // Prints: Opt(VOID)
```

Contains check

Returns true is this String contains that String

"abc".contains("cd").tp // Prints: false

Check if ends with

Returns true this String ends with that String

"abc".endsWith("bc").tp // Prints: true

Check if equals ignore case

Returns true this and that String are equal, if upper and lower case Chars are considered equal

"aBc".equalsIgnoreCase("ABC").tp // Prints: true

Value position

Optionally returns position of the specified `x`
```
"abcd_abcd_".indexOfOpt("d_a").tp // Prints: Opt(3)
```

Source of indexes

Source of indexes for each occurrence of `x`
```
"abcd_abcd_abcd_abcd_abcd".indexOfStream("bc").tp // Prints Stream(1, 6, 11, 16, 21)
```

Char index

Optionally returns index of the last Char passing the let function
```
    "abcd_abcd_".lastCharIndexOpt(_ >= 'd', 4).tp // Prints: Opt(3)
    "abcd_abcd_".lastCharIndexOpt('x' <> 'z') tp  // Prints: Opt(VOID)
```

Value position

Optionally returns last position of the specified `x`
```
"abcd_abcd_abcd_".lastIndexOfOpt("d_a").tp // Prints: Opt(8)
```

Check if begins with

Returns true this String starts with that String

"abc".startsWith("ab").tp // Prints: true