鎽樺彇JavaScript鐨勭涓€棰楁槑鐝狅細瀛楃鐨勮壓鏈?/h二>
鍦↗avaScript缂栫▼鐨勪笘鐣岄噷锛屾瘡涓€涓瓧绗﹂兘鏄竴棰楀疂鐭筹紝绛夊緟鎴戜滑鍘诲彂鐜板拰鍒╃敤銆傚瓧绗︿覆鎿嶄綔锛屽挨鍏舵槸瀵瑰瓧绗︿覆鐨勯瀛楃鎻愬彇锛屽彲鑳芥槸寮€鍙戜腑鐪嬩技绠€鍗曞嵈鍙堟瀬涓洪噸瑕佺殑浠诲姟銆傚湪鏈枃涓紝鎴戜滑灏嗘帰璁ㄥ浣曞阀濡欏湴浠庡瓧绗︿覆涓彁鍙栫涓€涓瓧绗︼紝鍒嗕韩涓€浜涘疄鐢ㄧ殑灏忔妧宸э紝璁╀綘杞绘澗鎺屾彙JavaScript澶勭悊杩欎釜鍩烘湰鍗寸簿缁嗙殑鎿嶄綔銆?/p>
Why绗竴瀛楃濡傛閲嶈锛?/h二>
浣犳垨璁镐細闂紝鍦ㄥ瓧绗︿覆澶勭悊涓紝棣?b>瀛楃涓轰綍濡傛閲嶈锛熺瓟妗堟湁寰堝銆傞瀛楃甯稿父琚敤鏉ュ垽鏂瓧绗︿覆鐨勭被鍨嬶紝濡傛暟瀛椼€佸瓧姣嶆垨绗﹀彿銆傚湪鎺掑簭銆佸垎缁勬垨鑰呮牸寮忓寲鎿嶄綔涓紝棣栧瓧绗︽槸鍏抽敭銆備緥濡傦紝鐞嗚В棣栧瓧绗︾殑Unicode缂栫爜瀵逛簬鍥介檯鍖栧簲鐢ㄥ挨涓洪噸瑕併€?/p>
JavaScript鎻愬彇棣栧瓧绗︾殑甯歌鏂规硶
鍦↗avaScript涓紝鎻愬彇瀛楃涓茬殑棣栧瓧绗︽湁鍑犵甯歌鏂规硶銆傚湪杩欓噷锛屾垜浠皢浠嬬粛鏈€鐩存帴鍜?b>绠€娲?/b>鐨勬柟娉曪細
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浣跨敤charAt鏂规硶
瀛楃涓茬殑
charAt鏂规硶鍙互鐩存帴璁块棶鎸囧畾浣嶇疆鐨勫瓧绗︼紝渚嬪锛岃幏鍙栭瀛楃锛?/p>const str = 'Hello, World!'; const firstChar = str.charAt(零); // 缁撴灉: 'H'
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绱㈠紩
瀛楃涓插湪JavaScript涓湰璐ㄤ笂鏄彲浠ョ储寮曠殑鏁扮粍锛屽彲浠ョ洿鎺ユ柟鎷彿杩愮畻绗﹁幏鍙栭瀛楃锛?/p>
const str = 'JavaScript'; const firstChar = str[零]; // 缁撴灉: 'J'
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浣跨敤
substring鎴?code>slice鏂规硶杩欎簺鏂规硶鎻愪緵鎴彇瀛楃涓插瓙涓茬殑鍔熻兘锛屼絾鍙渶瑕佹埅鍙栭瀛楃渚块潪甯搁珮鏁堬細
const str = 'Supercalifragilisticexpialidocious'; const firstChar = str.substring(零, 一); // 缁撴灉: 'S' // 鎴栬€? const firstChar = str.slice(零, 一); // 缁撴灉: 'S'
鎻愬彇棣栧瓧绗︾殑灏忔妧宸?/h二>
鎻愬彇棣栧瓧绗﹁櫧鐒剁湅浼肩畝鍗曪紝浣嗘湁涓€浜涘€煎緱娉ㄦ剰鐨勬妧宸э細
鍏煎绌哄瓧绗?/b>
澶勭悊绌哄瓧绗︿覆鏃讹紝娉ㄦ剰閬垮厤閿欒锛?/p> const str = ""; const firstChar = str[零] || str.charAt(零) || ''; // 缁撴灉: ''
鑰冭檻Unicode瀛楃
褰撳瓧绗︿覆鍖呭惈Unicode瀛楃鏃讹紝瀛楃绱㈠紩鐨勫鏉傚彲鑳藉鍔犮€備娇鐢?code>codePointAt鏇翠匠锛?/p>
const str = '馃捇';if (str.length > 零) { const firstCharCode = str.codePointAt(零); const firstChar = String.fromCodePoint(firstCharCode); // 缁撴灉: '馃捇'} 鎴戜滑娣卞叆鎺㈣浜嗗浣曞湪JavaScript涓伒娲绘彁鍙栧瓧绗︿覆鐨勯瀛楃銆傚湪鏃ュ父寮€鍙戜腑锛岀悊瑙ｅ拰鎺屾彙杩欎簺鎶€宸т笉浠呭彲浠ラ珮鏁堣В鍐抽棶棰橈紝鏇磋兘璁╀唬鐮佹洿鏈夋妧宸у拰鎵╁睍銆傝浣忥紝姣忎竴涓粏灏忔搷浣滅殑绱Н锛岄兘鑳借浣犵殑浠ｇ爜鍙樺緱鏇村姞绮惧僵銆傚笇鏈涙湰鏂囩殑鍒嗕韩锛屼綘宸茬粡鑳藉鏇存湁淇″績鍦拌繍鐢↗avaScript鎴彇棣栧瓧绗︾殑鎵嬫瑙ｅ喅瀹為檯闂銆?/p>
