JS ahanoa forEach rite te whakatinanatanga

JavaScript wetereo whakarato te kaha ki te ngā taurangi ki huānga me ngā. Access ki te mea timatanga taea te uru mā taupū me ingoa i roto i te ngā huringa.

Otiia e kore e he reira tonu taea ki te mohio te maha o ngā āhuatanga i roto i te kohinga i wa hoahoa me he kahore tonu watea ki te whakamahi i ngā i te wetereo semantics roto ratou.

hoahoa Tauhira

tauākī koropiko Pūnoa "mo (var i = 0; i

var i = 0;
i {... aData [i] (typeof aData [i] = 'koretautuhi'!); ... ++ i; }

ina he mōhiotia te maha o ngā huānga.

Ka taea hoki te hanga rerekē hātepe mō te whakakī me te tukatuka ngohi, engari ko reira nui atu watea ki te whakamahi i te hou, rerekē hou.

Classic pai ina hiahia koe ki te tukatuka i te HR pätai (ingoa, ingoa tuatahi, tūnga), kāri mō te taputapu (tauira, kaihanga, kaihoko, te rā o te hoko), me ētahi atu raraunga kahore e e te hanganga huri me te tohu i te moni tāpiripiri.

A, no te te huānga ngohi i roto ano ko te ahanoa hanganga ranei e kua ona ake āhuatanga me ngā tikanga, e kore e taea akakoromaki i akiaki matarohia nui me te kounga, me tango he ngohi tikanga rerekē.

koropiko forEach

Ko te akiaki, ko te āhuatanga faufaa faaiteraa tūturu huānga ngohi. Hoahoa JS ngohi forEach, i roto i ahua rerekē i te mua (whāngai i roto i ētahi atu reo), putanga, ka taea tatou ki te whakarato i te ngohi o te whai wāhi ki te whakaatu i to ratou āhuatanga i roto i te rā o tona huānga.

Whakaaro kotahi ngohi Kei te ara (ratou āhuatanga kounga me te ine), me tetahi atu ngohi - waka e taea haere anake i runga i etahi rori me i rerekē tāke rōrahi wahie, i.e. he nui ano hoki te tawhiti i waenganui i kai.

I roto i te whakatinanatanga taua me tango hātepe tika rite te pūtake, hei tauira, ara, me te whiriwhiri i nga waka e ka waiho ki te peia runga reira taea. A he pai taua mea, ki te te ara, me te motokā, korero i roto i te hōtaka rite ahanoa, "kitea ratou." Ko te tono tūturu o te hōtaka ahanoa-hāngai, i, i roto i era atu mea, e kore e hiahia ana ki te huri i te hātepe mō te huri ara, me te motokā kohikohinga tenei, aunoa tikanga ai mo te rori hanga, tiaki motokā, me te pera i runga i

Tū i JS hanganga forEach ko tino māmā: "aData.forEach (fData):", i reira fData - he mahi tono e te ki i ia huānga o te ngohi aData:

mahi fData (uara, taupū) {sText + = taupū + '=' + uara + '; '; }.

Ki te māngai te raraunga pūtake te whai ake nei:

var aData = [1,2,3,4];
aData.push (11);
aData.push (22);
aData.push (44);
aData.push ( 'rārangi 1');
aData.push ( 'rārangi 2');

var sText = '',

te hua o taua whakamahi JS forEach ka:

"0 = 1 1 = 2 2 = 3 3 = 4 4 = 11: 5 = 22, 6 = 44, 7 = rārangi 1, 8 = aho 2;".

Āhuatanga ngā huānga

Ahanoa i runga i JavaScript - motuhake. Mā te taonga i runga i tenei reo ko tino rerekē i implementations i ētahi atu reo. Ahanoa - Ko te ngohi o ngā āhuatanga me ngā tikanga tenei i roto iho. Ki te whakamutunga mau mahi te mahi, te tiaki whakatika tona ihirangi atu waho taonga, huānga, taurangi ranei ranei.

Ko te ahanoa e haere mai ana ki te ngohi rite papa i runga i te Filmstrip, ina iterating i JS hanganga ahanoa forEach hanga he semantics hou: hoahoa tikanga tāupe.

Na, ko te ara e ratou e taea e ki te whiriwhiri i te motokā e taea eke ki runga ki a ratou, a ka kua tātari i te ra whakamutunga ara e wātea ana. Ki te kore koe e whakarongo, e te hapanga i roto i tenei kōwhiringa hōtaka atu waehere pono, te mahi - ki te whakatau i te ara o te tuku - hanga JS forEach hanga i roto i te otinga e whai hua, me te ohie: whakawhānui i te ara o rori, tīpako i te mīhini, me te mahia i te tuku o taonga.

Ki te ara, rori, me te mīhini - ngā huānga o ngā, kei te nui raweketia te hātepe. kia mea he ke e te putanga o JS hanganga forEach rite te roa roa i roto i te haere mai. Heoi, ahakoa te tapatahi o te wāhi, i roto i te mahi he reira uaua ki te whakatinana.

Mahi JS forEach me tūturu ahanoa

Whakaaro kaiwhakawhanake hou mahi ki ngā waia hoki hōtaka, engari e kore e ahanoa o te raruraru tūturu. Ehara i noa i matau e te hunga o te motokā ara, te ara, te tawhiti ...

Kua tipu hōtaka ahanoa-hāngai ara tataramoa, a tuku iho kua riro ki te waihanga i tētahi ngohi ahanoa hōtaka, puka, pātene, ara pouaka kōwhiringa, me ētahi atu

I tua atu, whakamana JS forEach me ētahi atu ngā hanganga reo e i roto i te pūtirotiro o te manuhiri e hopoi mai i roto i te mahi fakangatangata nui. Ehara i te mea rite ki te faaite i tona waehere katoa kaiwhakawhanake. tauira tōtika o te whakamahi o ngā huānga me ngā kohinga o ngā taonga tūturu - te ara pai ki te whakapai ake i te matauranga.

Heoi, ko te wātea o JavaScript waehere mō kāore i whakamahi kaiwhakawhanake he pānga autaki i runga i te whanaketanga o ngā whakaaro whaihua mō te taonga hihiri me te tūturu-ao. e kore ko JS forEach hanga ano tino, me te mea te whanaketanga o ratou semantics ki hei aronga rawa whaihua.