go语言range字符串 go语言字符串转换成数字
如何理解Golang中的range语句
你把它理解为遍历么，结合for循环。
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假设有一个初始化好的数组(table)或者切片(slice)的table，且table长度为10：
for i, value := range table {
fmt.Printf("i=%v, value=%v\n", i, value)
}
则会执行fmt.Printf10次，且这10次的【i】的值分别是从0~9，也就相当于
for i := 0; i len(table); i++ {
fmt.Printf("i=%v, value=%v\n", i, table[i])
}
如果把上边的数组或者切片换成map
for key, value := range table {
fmt.Pritnf("key=%v, value=%v\n", key, value)
}
则类似上边的过程把map里边的key-value键值对一 一遍历
如何使用Range截取字符串
func someMethodOfRange() {
/**
* 字符串与Range的用法
*/
//1.截取字符串（字符）在整个字符串中所在的位置，返回的类型为 Index
var str = "abcdefghi"
let startIndex = str.rangeOfString("cde")!.startIndex
print(startIndex)//2
let endIndex = str.rangeOfString("cde")!.endIndex
print(endIndex)//5
//2、根据字符串的索引来获取对应的字符
let text = "abcdefghi"
let index2 = text.startIndex.advancedBy(2) //will call succ 2 times
print(index2)//2
let lastChar: Character = text[index2] //now we can index!
print(lastChar)//c
let lastChar2 = text.characters[index2] //will do the same
print(lastChar2)//c
//3.截取字符串（字符）在整个字符串中所在的范围 、返回值类型RangeIndex
let range: RangeString.Index = text.rangeOfString("bc")!
print(range)//1..3
let index3: Int = text.startIndex.distanceTo(range.startIndex)
print(index3)//1
let index4: Int = text.startIndex.distanceTo(range.endIndex)
print(index4)//3
print(text.characters.count)//9
let abc = "@救123"
print(abc.characters.count)//5
//4.0 Index -- Int
let range: RangeString.Index = self.text!.rangeOfString(text)!
let index3: Int = self.text!.startIndex.distanceTo(range.startIndex)
let index4: Int = self.text!.startIndex.distanceTo(range.endIndex)
//一个字符串。指标值可以通过调用predecessor()方法访问其 先前 指标，其指标successor()下一个指标 调用方法。字符串中的任何指标可从任何其他指数通过把这些方法结合在一起，或通过使用--（_：）方法。试图访问一个字符串的范围以外的索引会引发一个运行时错误
let greeting = "123456789"
greeting[greeting.startIndex]
print(greeting)
print("起使位置\(greeting.startIndex)")//0
print("终点位置\(greeting.endIndex)")//9
print(greeting[greeting.startIndex])//1
greeting[greeting.endIndex.predecessor()]
print(greeting[greeting.endIndex.predecessor()])//9
print(greeting.endIndex.predecessor())//8
print(greeting.startIndex.successor())//1
greeting[greeting.startIndex.successor()]
print(greeting[greeting.startIndex.successor()])//2
let index = greeting.startIndex.advancedBy(7)
greeting[index]
print(greeting[index])//8
//试图在字符串的范围以外的索引处访问一个字符，将引发一个运行时错误。”
//greeting[greeting.startIndex.predecessor()]//cuowu
//print(greeting[greeting.endIndex])//cuowu
//越界
//greeting[greeting.endIndex]
//greeting.endIndex.successor()
//““Use the indices property of the characters property to 创建一个字符串中访问单个字符的所有索引的范围。”
for index in greeting.characters.indices {
print("\(greeting[index])",terminator: "")
// print("**")
}
}
//相关的应用：在UILabel里面，不同文本显示不同字体的大小
extension UILabel {
/*
*设置text的字体大小
*/
func settingLabelTextKitWithText(text:String,font:UIFont) {
if text.isEmpty {//通过检查其 Boolean 类型的 isEmpty 属性来判断该字符串是否为空：
print("什么都没有")
return
}else {
//方法1
let attrstring:NSMutableAttributedString =NSMutableAttributedString(string: self.text!)
let str = NSString(string: self.text!)
let theRange = str.rangeOfString(text)
attrstring.addAttribute(NSFontAttributeName, value: font, range: theRange)
self.attributedText = attrstring
/**
// 方法2
let attrstring:NSMutableAttributedString = NSMutableAttributedString(string: self.text!)
let range: RangeString.Index = self.text!.rangeOfString(text)!
let index3: Int = self.text!.startIndex.distanceTo(range.startIndex)
let index4: Int = self.text!.startIndex.distanceTo(range.endIndex)
attrstring.addAttribute(NSFontAttributeName, value: font, range: NSMakeRange(index3, index4 - index3))
self.attributedText = attrstring
*/
}
}
go语言怎么输出字符串中的某个中文字符？
for index,val := range a {
if val == '好' {
fmt.println(index,x)
}
}
对string做range得到的val是int32类型，直接用单引号比较就行
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