Eyona ngxaki ngokujonga ukuba umtya uqulathe kuphela amanani apheleleyo amadijithi kukuba akukho mgangatho uchaziweyo wendlela yokwenza oku. Oku kunokukhokelela ekuphunyezweni okwahlukeneyo kubuyise iziphumo ezahlukeneyo, ezinokuba nzima ukuziqonda kunye nokulungiswa kweempazamo.
I want to check if a string only contains integer digits numbers. For example: <code>var str = "123"; // return true; var str = "123a"; // return false; </code> A: You can use <code>/^d+$/.test(str)</code>. This will test whether the string consists of one or more digits. If you want to allow for a leading minus sign, then use <code>/^-?d+$/.test(str)</code>. If you want to allow for an optional decimal point and fractional part, then use <code>/^-?d+(.d+)?$/.test(str)</code>. If you want to allow for an optional exponent, then use <code>/^-?(d+(.d*)?|.d+)([eE][-+]?d+)?$/.test(str)</code>. The last two expressions are the ones used by the built-in function <code>isFinite()</code>, which is what you should be using if your goal is to test whether a string can be converted into a number. (If your goal is something else, please edit your question.)
Imiqathango
Iimeko sisixhobo esinamandla kwiJavaScript. Bakuvumela ukuba ulawule ukuhamba kwekhowudi yakho ngokusekelwe kwiimeko ezithile ezihlangatyezwayo.
Olunye usebenziso oluqhelekileyo lweemeko kukukhangela ukuba i-variable ilingana nexabiso elithile. Umzekelo, unokufuna ukubonisa umyalezo wemposiso ukuba igalelo lomsebenzisi alisebenzi.
Ungasebenzisa i-if statement ukuvavanya ukuba imeko iyinyani okanye bubuxoki. Umzekelo wekhowudi ulandelayo ujonga ukuba igalelo lomsebenzisi liphakathi ko-1 no-10:
ukuba (Igalelo lomsebenzisi <= 10) {// Bonisa umyalezo wemposiso } enye into {// Bonisa impendulo eqhelekileyo } Unokusebenzisa isitatimenti sokutshintsha ukuvavanya iimeko ezininzi ngaxeshanye. Lo mzekelo wekhowudi ulandelayo ujonga ukuba igalelo lomsebenzisi liphakathi ko-1 no-10, linobude ubuncinane bamagama ama-3, kwaye iqala ngonobumba: tshintsha (userInput) { case "1": case "2": case "3": case "a": case "b": case "c": break; okungagqibekanga: // Bonisa umyalezo wemposiso }
Ukuba, Okunye
Ukuba ngumsebenzisi onemiqathango kwiJavaScript. Ikuvumela ukuba ukhethe phakathi kweziphumo ezibini ezinokubakho. Isiphumo sokuqala yimeko, kwaye isiphumo sesibini sisiphumo se-if statement.
Ukuba ufuna ukujonga ukuba inani lilinganayo okanye aliqhelekanga, ungasebenzisa le khowudi ilandelayo:
ukuba (inani % 2 == 0) {//nokuba } enye into {//odd }
Elinye igatya liza kuphunyezwa ukuba inani alililo.
