以下是软件版本号:
"1.0", "1.0.1", "2.0", "2.0.0.1", "2.0.1"
我怎么比较呢?
假设正确的顺序是:
"1.0", "1.0.1", "2.0", "2.0.0.1", "2.0.1"
想法很简单…
读第一个数字,然后,第二个,第三个…
但是我不能将版本号转换为浮点数…
你也可以像这样看到版本号:
"1.0.0.0", "1.0.1.0", "2.0.0.0", "2.0.0.1", "2.0.1.0"
这样可以更清楚地看到背后的想法。
但是,我怎样才能把它转换成计算机程序呢?
功能简单简短:
function isNewerVersion (oldVer, newVer) {
const oldParts = oldVer.split('.')
const newParts = newVer.split('.')
for (var i = 0; i < newParts.length; i++) {
const a = ~~newParts[i] // parse int
const b = ~~oldParts[i] // parse int
if (a > b) return true
if (a < b) return false
}
return false
}
测试:
isNewerVersion('1.0', '2.0') // true
isNewerVersion('1.0', '1.0.1') // true
isNewerVersion('1.0.1', '1.0.10') // true
isNewerVersion('1.0.1', '1.0.1') // false
isNewerVersion('2.0', '1.0') // false
isNewerVersion('2', '1.0') // false
isNewerVersion('2.0.0.0.0.1', '2.1') // true
isNewerVersion('2.0.0.0.0.1', '2.0') // false
这里有一个面向对象的有趣方法:
function versionString(str) {
var parts = str.split('.');
this.product = parts.length > 0 ? parts[0] * 1 : 0;
this.major = parts.length > 1 ? parts[1] * 1 : 0;
this.minor = parts.length > 2 ? parts[2] * 1 : 0;
this.build = parts.length > 3 ? parts[3] * 1 : 0;
this.compareTo = function(vStr){
vStr = this._isVersionString(vStr) ? vStr : new versionString(vStr);
return this.compare(this, vStr);
};
this.toString = function(){
return this.product + "." + this.major + "." + this.minor + "." + this.build;
}
this.compare = function (str1, str2) {
var vs1 = this._isVersionString(str1) ? str1 : new versionString(str1);
var vs2 = this._isVersionString(str2) ? str2 : new versionString(str2);
if (this._compareNumbers(vs1.product, vs2.product) == 0) {
if (this._compareNumbers(vs1.major, vs2.major) == 0) {
if (this._compareNumbers(vs1.minor, vs2.minor) == 0) {
return this._compareNumbers(vs1.build, vs2.build);
} else {
return this._compareNumbers(vs1.minor, vs2.minor);
}
} else {
return this._compareNumbers(vs1.major, vs2.major);
}
} else {
return this._compareNumbers(vs1.product, vs2.product);
}
};
this._isVersionString = function (str) {
return str !== undefined && str.build !== undefined;
};
this._compareNumbers = function (n1, n2) {
if (n1 > n2) {
return 1;
} else if (n1 < n2) {
return -1;
} else {
return 0;
}
};
}
还有一些测试:
var v1 = new versionString("1.0");
var v2 = new versionString("1.0.1");
var v3 = new versionString("2.0");
var v4 = new versionString("2.0.0.1");
var v5 = new versionString("2.0.1");
alert(v1.compareTo("1.4.2"));
alert(v3.compareTo(v1));
alert(v5.compareTo(v4));
alert(v4.compareTo(v5));
alert(v5.compareTo(v5));
// Return 1 if a > b
// Return -1 if a < b
// Return 0 if a == b
function compare(a, b) {
if (a === b) {
return 0;
}
var a_components = a.split(".");
var b_components = b.split(".");
var len = Math.min(a_components.length, b_components.length);
// loop while the components are equal
for (var i = 0; i < len; i++) {
// A bigger than B
if (parseInt(a_components[i]) > parseInt(b_components[i])) {
return 1;
}
// B bigger than A
if (parseInt(a_components[i]) < parseInt(b_components[i])) {
return -1;
}
}
// If one's a prefix of the other, the longer one is greater.
if (a_components.length > b_components.length) {
return 1;
}
if (a_components.length < b_components.length) {
return -1;
}
// Otherwise they are the same.
return 0;
}
console.log(compare("1", "2"));
console.log(compare("2", "1"));
console.log(compare("1.0", "1.0"));
console.log(compare("2.0", "1.0"));
console.log(compare("1.0", "2.0"));
console.log(compare("1.0.1", "1.0"));
我找到了最简单的方法来比较它们,但我不确定这是否是你想要的。
当我在控制台中运行下面的代码时,它是有意义的,并且使用sort()方法,我可以获得版本字符串的排序数组。它是根据字母顺序排列的。
"1.0" < "1.0.1" //true
var arr = ["1.0.1", "1.0", "3.2.0", "1.3"]
arr.sort(); //["1.0", "1.0.1", "1.3", "3.2.0"]
这个非常小,但非常快的比较函数接受每个段的任何长度和任何数字大小的版本号。
返回值:
-如果a < b,则数字< 0
-如果是> b,则为> 0
如果a = b - 0
所以你可以使用它作为array。sort()的比较函数;
编辑:修正了版本剥离尾随零识别“1”和“1.0.0”相等的错误
function cmpVersions (a, b) {
var i, diff;
var regExStrip0 = /(\.0+)+$/;
var segmentsA = a.replace(regExStrip0, '').split('.');
var segmentsB = b.replace(regExStrip0, '').split('.');
var l = Math.min(segmentsA.length, segmentsB.length);
for (i = 0; i < l; i++) {
diff = parseInt(segmentsA[i], 10) - parseInt(segmentsB[i], 10);
if (diff) {
return diff;
}
}
return segmentsA.length - segmentsB.length;
}
// TEST
console.log(
['2.5.10.4159',
'1.0.0',
'0.5',
'0.4.1',
'1',
'1.1',
'0.0.0',
'2.5.0',
'2',
'0.0',
'2.5.10',
'10.5',
'1.25.4',
'1.2.15'].sort(cmpVersions));
// Result:
// ["0.0.0", "0.0", "0.4.1", "0.5", "1.0.0", "1", "1.1", "1.2.15", "1.25.4", "2", "2.5.0", "2.5.10", "2.5.10.4159", "10.5"]
比较不同条件下的功能:
const compareVer = (ver1, middle, ver2) => {
const res = new Intl.Collator("en").compare(ver1, ver2)
let comp
switch (middle) {
case "=":
comp = 0 === res
break
case ">":
comp = 1 === res
break
case ">=":
comp = 1 === res || 0 === res
break
case "<":
comp = -1 === res
break
case "<=":
comp = -1 === res || 0 === res
break
}
return comp
}
console.log(compareVer("1.0.2", "=", "1.0.2")) // true
console.log(compareVer("1.0.3", ">", "1.0.2")) // true
console.log(compareVer("1.0.1", ">=", "1.0.2")) // false
console.log(compareVer("1.0.3", ">=", "1.0.2")) // true
console.log(compareVer("1.0.1", "<", "1.0.2")) // true
console.log(compareVer("1.0.1", "<=", "1.0.2")) // true