英文:
goLang. call ".Front()" for a string list. But returns error saying string list has no Front method
问题
我有这样的代码：
t := strings.FieldsFunc(value, extract_word)
fmt.Println("t:", len(t), t)
m := make(map[string]int)
for word := t.Front(); word != nil; word = word.Next() {
m[word.Value.(string)]++
}
它报错了：
t.Front undefined (type []string has no field or method Front)
我知道列表有 Front() 方法。http://golang.org/pkg/container/list/ 但为什么在这里会报错呢？我很困惑，需要帮助。谢谢！
英文:
I have code like this
t := strings.FieldsFunc(value, extract_word)
fmt.Println("t:", len(t),t)
m := make(map[string]int)
for word := t.Front(); word != nil; word=word.Next(){
m[word]++
}
and it gets this error
t.Front undefined (type []string has no field or method Front)
I know list has Front() method.
http://golang.org/pkg/container/list/
but why it complains here?
so confused, need help.
thank you!
答案1
得分: 2
[]T在其他语言（如Python）中被称为“列表”，但在Go语言中被称为“切片”http://golang.org/ref/spec#Slice_types。
切片的元素范围从0到len(slice)-1，可以使用类似C语言数组访问的方式来访问它们。通常认为切片的“前面”是slice[0]，但如果你将切片用于实现类似栈的数据结构，你可以考虑不同的索引作为前面。
Go语言中没有任何内置类型定义了方法，但是有一些内置函数可以接受它们作为参数，比如len函数。
你提到的包实现了List类型。正如顶部的文档所说，“Package list实现了一个双向链表。”你可以通过调用list.New()来创建这个双向链表，并且它具有Front方法，以及包文档中列出的其他方法。
英文:
[]T is not a "list" as it's referred to in other languages (e.g. Python). In Go, it's referred to as the "Slice" http://golang.org/ref/spec#Slice_types
Its elements range from 0 to len(slice)-1, and are accessed with C-like array access notation. The "front" of the slice is generally considered slice[0], though you may consider a different index the front if you're using a slice to implement something like, e.g., a stack.
No built-in type in Go has any methods defined on it, but do have built-in functions that take them as arguments, such as len.
The package you linked to implements the List type. As the documentation at the top says "Package list implements a doubly linked list." This doubly linked list, which you can create by calling list.New(), has a Front method, among the others listed in the package documentation.
答案2
得分: 1
t不是一个List，它是一个字符串切片（切片和列表不是同一种东西）。切片的第一个元素是[0]。
我认为你指的for循环是这样的（未经测试）：
for _, word := range t {
m[word]++
}
英文:
t is not a List. It is a slice of strings (slices and Lists are not the same thing). The first element of a slice is [0].
I believe the for loop you mean is this (untested):
for _, word := range t {
m[word]++
}
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