# IntlChar::istitle

(PHP 7, PHP 8)

IntlChar::istitle — Check if code point is a titlecase letter

### 说明

public static IntlChar::istitle(int|string `$codepoint`): ?bool

Determines whether the specified code point is a titlecase letter.

`true` for general category "Lt" (titlecase letter).

### 参数

`codepoint`

  The int codepoint value (e.g. `0x2603` for U+2603 SNOWMAN), or the character encoded as a UTF-8 string (e.g. `"\u{2603}"`)

### 返回值

Returns `true` if `codepoint` is a titlecase letter, `false` if not. Returns `null` on failure.

### 示例

示例 #1 Testing different code points

`<?php
// Latin Capital Letter Dz with Caron U+01C4
var_dump(IntlChar::istitle("Ǆ"));
// Latin Capital Letter D with Small Letter Z with Caron U+01C5
var_dump(IntlChar::istitle("ǅ"));
// Latin Small Letter Dz with Caron U+01C6
var_dump(IntlChar::istitle("ǆ"));
// Greek Capital Letter Alpha with Prosgegrammeni U+1FBC
var_dump(IntlChar::istitle("ᾼ"));
// Greek Small Letter Alpha with Ypogegrammeni U+1FB3
var_dump(IntlChar::istitle("ᾳ"));
// Greek Capital Letter Alpha U+0391
var_dump(IntlChar::istitle("Α"));
?>`

以上示例会输出：

    bool(false)
    bool(true)
    bool(false)
    bool(true)
    bool(false)
    bool(false)

### 参见

- IntlChar::isupper() - Check if code point has the general category "Lu" (uppercase letter)
- IntlChar::islower() - Check if code point is a lowercase letter
- IntlChar::totitle() - Make Unicode character titlecase

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