Html 如何比较golang中html/template中列表的长度？
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How to compare the length of a list in html/template in golang?
提问by Dany
I am trying to compare the length of a list in golang html/template. But it is loading forever in html.
我正在尝试比较 golang html/template 中列表的长度。但它在 html 中永远加载。
{{ $length := len .SearchData }} {{ if eq $length "0" }}
Sorry. No matching results found
{{ end }}
Could anyone help me with this?
有人可以帮我解决这个问题吗？
回答by Aruna Herath
From documentation,
从文档来看，
{{if pipeline}} T1 {{end}}: If the value of the pipeline is empty, no output is generated; otherwise, T1 is executed. The empty values are false, 0, any nil pointer or interface value, and any array, slice, map, or string of length zero. Dot is unaffected.
{{if pipeline}} T1 {{end}}：如果管道的值为空，则不产生输出；否则，执行T1。空值是 false、0、任何 nil 指针或接口值，以及任何长度为零的数组、切片、映射或字符串。点不受影响。
So if you want to check if the .SearchDataslice/array/map is empty just use,
因此，如果您想检查.SearchData切片/数组/映射是否为空，请使用，
{{if not .SearchData}} Nothing to show {{end}}
Even your code runs fine if string "0"is replaced by int 0
如果 string"0"被 int 替换，即使你的代码也能正常运行0
{{ $length := len .SearchData }} {{ if eq $length 0 }}
Sorry. No matching results found
{{ end }}
回答by emicklei
A shorter version
较短的版本
{{ if eq (len .SearchData) 0 }}
Sorry. No matching results found
{{ end }}
回答by Oleg Neumyvakin
There is {{ else }}for {{ range }}Works well for maps as well https://play.golang.org/p/7xJ1LXL2u09:
有{{ else }}适用{{ range }}于地图以及https://play.golang.org/p/7xJ1LXL2u09：
{{range $item := . }}
<span>{{ $item }}</span>
{{ else }}
<span>Sorry no rows here</span>
{{ end }}
