Learn JavaScript ARRAYS in 8 minutes! ð
Summary
TLDRãã®ãããªã§ã¯ãJavaScriptã®é åã«ã€ããŠèª¬æããŠããŸããé åã¯ãè€æ°ã®å€ãæ ŒçŽã§ãã倿°ã®ãããªæ§é ã§ããé åãäœæããã«ã¯ãå€ãè§æ¬åŒ§ã§å²ã¿ãã³ã³ãã§åºåããŸããèŠçŽ ã®ã€ã³ããã¯ã¹ã䜿ã£ãŠã¢ã¯ã»ã¹ããããé åã®é·ããååŸãããããæ¹æ³ã玹ä»ããèŠçŽ ã®è¿œå ãå逿¹æ³ïŒpush, pop, unshift, shiftïŒãåŠã³ãŸãããŸããforã«ãŒããæ¡åŒµforã«ãŒãã䜿ã£ãŠé åã®èŠçŽ ã衚瀺ããæ¹æ³ããé åã®äžŠã¹æ¿ãæ¹æ³ïŒsort, reverseïŒã«ã€ããŠãè§ŠããŠããŸããåå¿è ã«ãåããããããå®è·µçãªå 容ã§ãã
Takeaways
- ð é åã¯ãè€æ°ã®å€ãä¿æã§ãã倿°ã®ãããªæ§é ã§ãã
- ð é åã¯ãå€ãè§æ¬åŒ§ã[ ]ãã§å²ãããšã«ãã£ãŠäœæã§ããŸãã
- ð é åã®èŠçŽ ã«ã¯ã€ã³ããã¯ã¹ã䜿çšããŠã¢ã¯ã»ã¹ããŸããã€ã³ããã¯ã¹ã¯0ããå§ãŸããŸãã
- ð é åã®èŠçŽ ã倿Žããã«ã¯ããã®ã€ã³ããã¯ã¹ãæå®ããŠæ°ããå€ãä»£å ¥ããŸãã
- ð é åã®æ«å°Ÿã«èŠçŽ ã远å ããã«ã¯ã`push()` ã¡ãœããã䜿çšããŸãã
- ð é åã®æ«å°ŸããèŠçŽ ãåé€ããã«ã¯ã`pop()` ã¡ãœããã䜿çšããŸãã
- ð é åã®å é ã«èŠçŽ ã远å ããã«ã¯ã`unshift()` ã¡ãœããã䜿çšããŸãã
- ð é åã®å é ããèŠçŽ ãåé€ããã«ã¯ã`shift()` ã¡ãœããã䜿çšããŸãã
- ð é åã®é·ããååŸããã«ã¯ã`length` ããããã£ã䜿çšããŸãã
- ð é åå ã®ç¹å®ã®èŠçŽ ã®ã€ã³ããã¯ã¹ãæ€çŽ¢ããã«ã¯ã`indexOf()` ã¡ãœããã䜿çšããŸãã
- ð é åã®èŠçŽ ãã«ãŒãããŠè¡šç€ºããã«ã¯ã`for` ã«ãŒãããfor...ofãã«ãŒãã䜿çšã§ããŸãã
- ð é åãéé ã§è¡šç€ºããã«ã¯ã`for` ã«ãŒããéæ¹åã«èšå®ãããã`reverse()` ã¡ãœããã䜿çšããŸãã
- ð é åãã¢ã«ãã¡ãããé ã«äžŠã¹æ¿ããã«ã¯ã`sort()` ã¡ãœããã䜿çšããéé ã«ããã«ã¯ `reverse()` ã䜵çšããŸãã
Q & A
é åãšã¯äœã§ããïŒ
-é åã¯ãè€æ°ã®å€ãæ ŒçŽã§ãã倿°ã®ãããªæ§é ã§ããéåžžã®å€æ°ã¯1ã€ã®å€ããæ ŒçŽã§ããŸããããé åã¯è€æ°ã®å€ãæ ŒçŽã§ããŸããå€ã¯è§æ¬åŒ§ã§å²ã¿ãã«ã³ãã§åºåããŸãã
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é åã®èŠçŽ ã«ã¢ã¯ã»ã¹ããæ¹æ³ã¯ïŒ
-é åã®èŠçŽ ã«ã¢ã¯ã»ã¹ããã«ã¯ãé ååã®åŸã«è§æ¬åŒ§å ã«ã€ã³ããã¯ã¹çªå·ãèšè¿°ããŸããäŸãã°ã`fruits[0]`ã¯æåã®èŠçŽ ã«ã¢ã¯ã»ã¹ããŸãã
é åã®èŠçŽ ã倿Žããæ¹æ³ã¯ïŒ
-é åã®èŠçŽ ã倿Žããã«ã¯ãç¹å®ã®ã€ã³ããã¯ã¹çªå·ãæå®ããŠæ°ããå€ãä»£å ¥ããŸããäŸãã°ã`fruits[0] = 'ã³ã³ããã'`ã®ããã«èšè¿°ããŸãã
é åã«èŠçŽ ã远å ããæ¹æ³ã¯ïŒ
-é åã®æ«å°Ÿã«èŠçŽ ã远å ããã«ã¯ã`push`ã¡ãœããã䜿çšããŸããäŸãã°ã`fruits.push('ã³ã³ããã')`ã§é åã®æåŸã«ã³ã³ãããã远å ã§ããŸãã
é åããæåŸã®èŠçŽ ãåé€ããæ¹æ³ã¯ïŒ
-é åã®æåŸã®èŠçŽ ãåé€ããã«ã¯ã`pop`ã¡ãœããã䜿çšããŸããäŸãã°ã`fruits.pop()`ã§é åã®æåŸã®èŠçŽ ãåé€ãããŸãã
é åã®æåã«èŠçŽ ã远å ããæ¹æ³ã¯ïŒ
-é åã®å é ã«èŠçŽ ã远å ããã«ã¯ã`unshift`ã¡ãœããã䜿çšããŸããäŸãã°ã`fruits.unshift('ãã³ãŽãŒ')`ã§é åã®å é ã«ãã³ãŽãŒã远å ã§ããŸãã
é åã®æåã®èŠçŽ ãåé€ããæ¹æ³ã¯ïŒ
-é åã®æåã®èŠçŽ ãåé€ããã«ã¯ã`shift`ã¡ãœããã䜿çšããŸããäŸãã°ã`fruits.shift()`ã§é åã®æåã®èŠçŽ ãåé€ãããŸãã
é åã®é·ããååŸããæ¹æ³ã¯ïŒ
-é åã®é·ããååŸããã«ã¯ã`length`ããããã£ã䜿çšããŸããäŸãã°ã`fruits.length`ã§é åã®èŠçŽ æ°ãååŸã§ããŸãã
é åã®èŠçŽ ãååšããã確èªããæ¹æ³ã¯ïŒ
-é åå ã®èŠçŽ ãååšããã確èªããã«ã¯ã`indexOf`ã¡ãœããã䜿çšããŸããèŠçŽ ãèŠã€ããã°ãã®ã€ã³ããã¯ã¹ãè¿ããèŠã€ãããªããã°`-1`ãè¿ããŸãã
é åãã«ãŒãã§åŠçããæ¹æ³ã¯ïŒ
-é åãã«ãŒãã§åŠçããã«ã¯ã`for`ã«ãŒãã䜿çšããŸãã`for`ã«ãŒãã§ã¯ãã€ã³ããã¯ã¹ã䜿ã£ãŠåèŠçŽ ã«ã¢ã¯ã»ã¹ããåŠçãè¡ãããšãã§ããŸããããã«ã`for...of`æã䜿ã£ãŠç°¡æœã«ã«ãŒãåŠçããããšãã§ããŸãã
é åãéé ã«è¡šç€ºããæ¹æ³ã¯ïŒ
-é åãéé ã«è¡šç€ºããã«ã¯ã`reverse`ã¡ãœããã䜿çšããŸãã`fruits.reverse()`ãšèšè¿°ããããšã§ãé åã®èŠçŽ ãéé ã«äžŠã³æ¿ããããŸãã
é åããœãŒãããæ¹æ³ã¯ïŒ
-é åããœãŒãããã«ã¯ã`sort`ã¡ãœããã䜿çšããŸããäŸãã°ã`fruits.sort()`ã§ã¢ã«ãã¡ãããé ã«äžŠã³æ¿ããããŸããéé ã«ãœãŒãããã«ã¯ã`reverse`ã¡ãœããã远å ããŠ`fruits.sort().reverse()`ãšèšè¿°ããŸãã
Outlines

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