10種JavaScript交換值的方法
來源 | https://juejin.im/post/6873611999238946829
1、使用臨時(shí)變量
function swapWithTemp(num1, num2) {console.log(num1, num2)let temp = num1num1 = num2num2 = tempconsole.log(num1, num2)}swapWithTemp(66.66, 8.88)
2、使用算術(shù)運(yùn)算符+和-
function swapWithPlusMinus(num1, num2){console.log(num1, num2)num1 = num1 + num2num2 = num1 - num2num1 = num1 - num2console.log(num1, num2)}swapWithPlusMinus(66, 8)
num2 = num1-num2，同理，第一個(gè)數(shù)要換成第二個(gè)數(shù)的值，就是總的和減去第一個(gè)數(shù)的值，現(xiàn)在第一個(gè)數(shù)已經(jīng)是賦值給第二個(gè)數(shù)，所以直接減去第二數(shù)的值即可，也就是 num1 = num1-num2?。function swapWithPlusMinusShort(num1, num2){console.log(num1, num2)num2 = num1 + (num1 = num2) - num2console.log(num1, num2)}
(num1 = num2) ，這步，我們讓 num1 等于 num2 了，并且返回是 num2 的值，此時(shí) num1 值已交換。接著就用 num1 加上 ? (num1 = num2) 返回的值，也就是 num1 + num2 求和，然后思路就和上面分析的一樣了 。function swapWithPlusMinusShort(num1, num2){console.log(num1, num2)num2 = num1 + (num1 = num2) - num2console.log(num1, num2)}swapWithPlusMinusShort(2,3.1)
3、僅使用+或-運(yùn)算符
function swapWithPlus(num1, num2){console.log(num1, num2)num2 = num1 + (num1=num2, 0)console.log(num1, num2)}swapWithPlus(2.3,3.4)
()中，我們將num1分配給num2，旁邊的0是返回值。簡(jiǎn)而言之，第4行看起來是這樣的 :num2 = num1 + 0 => num2 = num1
4、?使用算術(shù)運(yùn)算符*和/
function swapWithMulDiv(num1, num2){console.log(num1, num2)num1 = num1*num2num2 = num1/num2num1 = num1/num2console.log(num1, num2)}swapWithMulDiv(2.3,3.4)
swapWithMulDiv(2.34,0)// 2.34 0// NaN NaN
function swapWithMulDiv(num1, num2){console.log(num1, num2)num1 = num1*num2num2 = num1/num2num1 = num1/num2console.log(num1, num2)}swapWithMulDiv(2.34,Infinity)// 2.34 Infinity// NaN NaN
function swapWithMulDiv(num1, num2){console.log(num1, num2)num1 = num1*num2num2 = num1/num2num1 = num1/num2console.log(num1, num2)}swapWithMulDiv(2.34,-Infinity)
function swapWithMulDivShort(num1, num2){console.log(num1, num2)num1 = num1*num2num2 = num1*(num1=num2)/num2num1 = num1/num2console.log(num1, num2)}swapWithMulDivShort(2.3,3.4)
5、僅使用*或/運(yùn)算符
num2 = num1 * 1 => num2 = num1
6、使用按位異或
0:function swapWithXOR(num1, num2){console.log(num1, num2)num1 = num1^num2;num2 = num1^num2;num1 = num1^num2;console.log(num1, num2)}swapWithXOR(10,1)
num1 = num1 ^ num2 = 1010 ^ 0001 = 1011num2 = num1 ^ num2 = 1011 ^ 0001 => 1010 => 10num1 = num1 ^ num2 = 1011 ^ 1010 => 0001 => 1
function swapWithXOR(num1, num2){console.log(num1, num2)num1 = num1^num2;num2 = num1^num2;num1 = num1^num2;console.log(num1, num2)}swapWithXOR(2.34,3.45)// 2.34 3.45// 3 2
function swapWithXOR(num1, num2){console.log(num1, num2)num1 = num1^num2;num2 = num1^num2;num1 = num1^num2;console.log(num1, num2)}swapWithXOR(-Infinity,Infinity)// -Infinity Infinity// 0 0
function swapWithXNOR(num1, num2){console.log(num1, num2)num1 = ~(num1^num2)num2 = ~(num1^num2)num1 = ~(num1^num2)console.log(num1, num2)}swapWithXNOR(10,1)
num1 = ~(num1 ^ num2) => ~(1010 ^ 1011)=> ~(1011) => ~11 => -12
-12 => 1100 => 0011 + 1 => 0100
num2 = ~(num1 ^ num2) => ~(0100 ^ 0001) => ~(0101) => ~5 => -6-6 => 0110 => 1001 + 1 => 1010 => 10
num1 = ~(num1 ^ num2) => ~(0100^ 1010) => ~(1110) => ~14 => -15-15 => 1111 => 0000 + 1 => 0001 => 1
function swapWithXNOR(num1, num2){console.log(num1, num2)num1 = ~(num1^num2)num2 = ~(num1^num2)num1 = ~(num1^num2)console.log(num1, num2)}swapWithXNOR(2.3,4.5)// 2.3 4.5// 4 2
8、在數(shù)組中賦值
function swapWithArray(num1, num2){console.log(num1, num2)num2 = [num1, num1 = num2][0]console.log(num1, num2)}swapWithArray(2.3,Infinity)// 2.3 Infinity// Infinity 2.3
9、使用解構(gòu)表達(dá)式
let num1 = 23.45let num2 = 45.67console.log(num1,num2)[num1,num2] = [num2,num1]console.log(num1,num2)
10、使用立即調(diào)用的函數(shù)表達(dá)式（IIFE）
function swapWithIIFE(num1,num2){console.log(num1,num2)num1 = (function (num2){ return num2; })(num2, num2=num1)console.log(num1,num2)}swapWithIIFE(2.3,3.4)
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