在 angular2 中打印 json 数组中的单个值
print a single value from json array in angular2
我是 angular2 的新手，我的问题是我有 json 对象，因为我必须只打印第一个 ID，即（预期输出 ID=564），但我在我的 [=21= 中获取所有 ID ] 找了很多都没有得到正确的答案，帮我解决这个问题。
<div *ngFor="let x of roilist">
<p >{{x[0].id}}</p></div>
{"items":[{"id":564,"sku":"MB570Z\/B","name":"Mini DisplayPort to DVI Adapter","attribute_set_id":4,"price":2800,"status":1,"visibility":4,"type_id":"simple","created_at":"2017-08-31 04:49:57","updated_at":"2017-08-31 05:06:31","weight":1,"extension_attributes":[],"product_links":[],"tier_prices":[],"custom_attributes":[{"attribute_code":"description","value":"Every Mac with a Mini DisplayPort allows you to connect an external display or projector using an adapter. You can use an external display as your main workspace or to extend your desktop, or you can work in mirrored mode with a projector so you can view what your audience sees.\r\nUse the Mini DisplayPort to DVI Adapter to connect an advanced digital monitor, such as the 20- or 23-inch Apple Cinema Display, that includes a DVI connector. Review the documentation or check with the manufacturer of your monitor to make sure you're choosing the right adapter."},{"attribute_code":"short_description","value":"Mini DisplayPort to DVI Adapter"},{"attribute_code":"image","value":"\/m\/i\/mini_displayport_to_dvi_adapter.jpg"},{"attribute_code":"small_image","value":"\/a\/p\/apple_hdmi_to_dvi_adapter.jpg"},{"attribute_code":"thumbnail","value":"\/a\/p\/apple_hdmi_to_dvi_adapter.jpg"},{"attribute_code":"options_container","value":"container2"},{"attribute_code":"required_options","value":"0"},{"attribute_code":"has_options","value":"0"},{"attribute_code":"url_key","value":"mini-displayport-to-dvi-adapter"},{"attribute_code":"msrp_display_actual_price_type","value":"0"},{"attribute_code":"tax_class_id","value":"2"},{"attribute_code":"gift_message_available","value":"0"},{"attribute_code":"is_featured","value":"0"},{"attribute_code":"gst_source","value":"28"},{"attribute_code":"hsncode","value":"85444299"},{"attribute_code":"gst_source_after_minprice","value":"-1"}]},{"id":565,"sku":"MB571Z\/A","name":"Mini DisplayPort to Dual-Link DVI Adapter","attribute_set_id":4,"price":9400,"status":1,"visibility":4,"type_id":"simple","created_at":"2017-08-31 04:49:58","updated_at":"2017-08-31 05:06:31","weight":1,"extension_attributes":[],"product_links":[],"tier_prices":[],"custom_attributes":[{"attribute_code":"description","value":"Every Mac with a Mini DisplayPort allows you to connect an external display or projector using an adaptor. You can use an external display as your main workspace or to extend your desktop, or you can work in mirrored mode with a projector so you can view what your audience sees.\nUse the Mini DisplayPort to Dual-Link DVI Adaptor to connect your Mac to a 30-inch display that includes a DVI connector, such as the 30-inch Apple Cinema Display HD, and enjoy the ultimate widescreen canvas with a resolution of 2560 by 1600 pixels."},{"attribute_code":"short_description","value":"Mini DisplayPort to Dual-Link DVI Adapter"},{"attribute_code":"image","value":"\/m\/i\/mini_displayport_to_dual-link_dvi_adapter.jpg"},{"attribute_code":"small_image","value":"\/m\/i\/mini_displayport_to_dual-link_dvi_adapter.jpg"},{"attribute_code":"thumbnail","value":"\/m\/i\/mini_displayport_to_dual-link_dvi_adapter.jpg"},{"attribute_code":"options_container","value":"container2"},{"attribute_code":"required_options","value":"0"},{"attribute_code":"has_options","value":"0"},{"attribute_code":"url_key","value":"mini-displayport-to-dual-link-dvi-adapter"},{"attribute_code":"msrp_display_actual_price_type","value":"0"},{"attribute_code":"tax_class_id","value":"2"},{"attribute_code":"gift_message_available","value":"0"},{"attribute_code":"is_featured","value":"0"},{"attribute_code":"gst_source","value":"28"},{"attribute_code":"hsncode","value":"85444299"},{"attribute_code":"gst_source_after_minprice","value":"-1"}]}],"search_criteria":{"filter_groups":[],"page_size":2},"total_count":92}
你应该不用 ngFor
<p >{{roilist[0].id}}</p></div>
我是 angular2 的新手，我的问题是我有 json 对象，因为我必须只打印第一个 ID，即（预期输出 ID=564），但我在我的 [=21= 中获取所有 ID ] 找了很多都没有得到正确的答案，帮我解决这个问题。
<div *ngFor="let x of roilist">
<p >{{x[0].id}}</p></div>
{"items":[{"id":564,"sku":"MB570Z\/B","name":"Mini DisplayPort to DVI Adapter","attribute_set_id":4,"price":2800,"status":1,"visibility":4,"type_id":"simple","created_at":"2017-08-31 04:49:57","updated_at":"2017-08-31 05:06:31","weight":1,"extension_attributes":[],"product_links":[],"tier_prices":[],"custom_attributes":[{"attribute_code":"description","value":"Every Mac with a Mini DisplayPort allows you to connect an external display or projector using an adapter. You can use an external display as your main workspace or to extend your desktop, or you can work in mirrored mode with a projector so you can view what your audience sees.\r\nUse the Mini DisplayPort to DVI Adapter to connect an advanced digital monitor, such as the 20- or 23-inch Apple Cinema Display, that includes a DVI connector. Review the documentation or check with the manufacturer of your monitor to make sure you're choosing the right adapter."},{"attribute_code":"short_description","value":"Mini DisplayPort to DVI Adapter"},{"attribute_code":"image","value":"\/m\/i\/mini_displayport_to_dvi_adapter.jpg"},{"attribute_code":"small_image","value":"\/a\/p\/apple_hdmi_to_dvi_adapter.jpg"},{"attribute_code":"thumbnail","value":"\/a\/p\/apple_hdmi_to_dvi_adapter.jpg"},{"attribute_code":"options_container","value":"container2"},{"attribute_code":"required_options","value":"0"},{"attribute_code":"has_options","value":"0"},{"attribute_code":"url_key","value":"mini-displayport-to-dvi-adapter"},{"attribute_code":"msrp_display_actual_price_type","value":"0"},{"attribute_code":"tax_class_id","value":"2"},{"attribute_code":"gift_message_available","value":"0"},{"attribute_code":"is_featured","value":"0"},{"attribute_code":"gst_source","value":"28"},{"attribute_code":"hsncode","value":"85444299"},{"attribute_code":"gst_source_after_minprice","value":"-1"}]},{"id":565,"sku":"MB571Z\/A","name":"Mini DisplayPort to Dual-Link DVI Adapter","attribute_set_id":4,"price":9400,"status":1,"visibility":4,"type_id":"simple","created_at":"2017-08-31 04:49:58","updated_at":"2017-08-31 05:06:31","weight":1,"extension_attributes":[],"product_links":[],"tier_prices":[],"custom_attributes":[{"attribute_code":"description","value":"Every Mac with a Mini DisplayPort allows you to connect an external display or projector using an adaptor. You can use an external display as your main workspace or to extend your desktop, or you can work in mirrored mode with a projector so you can view what your audience sees.\nUse the Mini DisplayPort to Dual-Link DVI Adaptor to connect your Mac to a 30-inch display that includes a DVI connector, such as the 30-inch Apple Cinema Display HD, and enjoy the ultimate widescreen canvas with a resolution of 2560 by 1600 pixels."},{"attribute_code":"short_description","value":"Mini DisplayPort to Dual-Link DVI Adapter"},{"attribute_code":"image","value":"\/m\/i\/mini_displayport_to_dual-link_dvi_adapter.jpg"},{"attribute_code":"small_image","value":"\/m\/i\/mini_displayport_to_dual-link_dvi_adapter.jpg"},{"attribute_code":"thumbnail","value":"\/m\/i\/mini_displayport_to_dual-link_dvi_adapter.jpg"},{"attribute_code":"options_container","value":"container2"},{"attribute_code":"required_options","value":"0"},{"attribute_code":"has_options","value":"0"},{"attribute_code":"url_key","value":"mini-displayport-to-dual-link-dvi-adapter"},{"attribute_code":"msrp_display_actual_price_type","value":"0"},{"attribute_code":"tax_class_id","value":"2"},{"attribute_code":"gift_message_available","value":"0"},{"attribute_code":"is_featured","value":"0"},{"attribute_code":"gst_source","value":"28"},{"attribute_code":"hsncode","value":"85444299"},{"attribute_code":"gst_source_after_minprice","value":"-1"}]}],"search_criteria":{"filter_groups":[],"page_size":2},"total_count":92}
你应该不用 ngFor
<p >{{roilist[0].id}}</p></div>