上篇文章 JavaScript 五种基本数据类型(上)的子妹篇。 如未作出特殊说明,本文例子均在Chrome控制台进行测试。
parseInt({})
NaN
Number({})
NaN
Number({0:1})
NaN
Number(true)
1
parseFloat(true)
NaN
parseInt(true)
NaN
Number("1")
1
parseFloat('1')
1
parseInt('1')
1
Number('1a')
NaN
parseFloat('a1')
NaN
parseInt('a1')
NaN
parseInt('33ee')
33
parseFloat('33ee')
33
-----------------------------Number转换规则更严格----------------------
Number('33 ee')
NaN
parseFloat('33 ee')
33
parseInt('33 ee')
33
---------------------------------Number转换规则更严格------------------
Number([])
0
Number([1])
1
Number([1,2])
NaN
Number(['1'])
1
Number(['12'])
12
Number(['12a'])
NaN
Number(['12 a'])
NaN
parseInt([])
NaN
parseInt([1])
1
parseInt([1,2])
1
parseInt(['1'])
1
parseInt(['12'])
12
parseInt(['12a'])
12
parseInt(['12 a'])
12
parseFloat([])
NaN
parseFloat([1])
1
parseFloat([1,2])
1
parseFloat(['1'])
1
parseFloat(['12'])
12
parseFloat(['12a'])
12
parseFloat
12
(2)Boolean,参数为Object对象、字符串、数字类型、数组对象:
Boolean({})
true
Boolean("a")//非空字符串都为true
true
Boolean("")
false
Boolean(1)
true
Boolean(2)
true
Boolean(0)
false
Boolean(1.1)
true
Boolean(-0)
false
Boolean(-1)
true
(3)String和toString,参数为Object对象、数组对象、数字、布尔类型:
----------------------------------string方法------------------------------------
String(true)
"true"
String(1)
"1"
String(1.1)
"1.1"
----------------------------------string方法------------------------------------
----------------------------------toString方法---------------------------------
var a = 1;a.toString()
"1"
var b = true; b.toString()
"true"
var c = []; c.toString()
""
var d = {}; d.toString()
"[object Object]"
var e = [1]; e.toString()
"1"
var c = ['1']; c.toString()
"1"
----------------------------------toString方法---------------------------------
关于toString(),详见 关于valueOf() 和 toString(),我们需要知道的事儿