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56 | 56 | // Array.prototype.sort() |
57 | 57 | // 3. Sort the inventors by birthdate, oldest to youngest |
58 | 58 | // 把这些人从大到小进行排序 |
59 | | - const ordered = inventors.sort(function(firstName, secondName) { |
60 | | - if(firstName.year > secondName.year) { |
61 | | - return 1; // 对 sort 函数,返回值为 -1 排在前面,1 排在后面 |
62 | | - } else { |
63 | | - return -1; |
64 | | - } |
65 | | - }); |
66 | | - console.table(ordered); |
| 59 | +// const ordered = inventors.sort(function(firstName, secondName) { |
| 60 | +// if(firstName.year > secondName.year) { |
| 61 | +// return 1; // 对 sort 函数,返回值为 -1 排在前面,1 排在后面 |
| 62 | +// } else { |
| 63 | +// return -1; |
| 64 | +// } |
| 65 | +// }); |
| 66 | +// console.table(ordered); |
67 | 67 |
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68 | 68 | const __ordered = inventors.sort((a, b) => (a > b) ? 1 : -1); |
69 | 69 | console.table(__ordered); |
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73 | 73 | // 4. How many years did all the inventors live |
74 | 74 | // 他们所有人一共活了多少岁 |
75 | 75 | // 下面三种写法是一样的效果 |
76 | | - var total = 0; |
77 | | - for(var i = 0; i < inventors.length; i++) { |
78 | | - total += inventors[i].passed - inventors[i].year; |
79 | | - } |
80 | | - console.log(total); |
81 | | - |
82 | | - var totalYears = inventors.reduce(function(total, inventor) { |
83 | | - return total + inventor.passed - inventor.year; |
84 | | - }, 0); |
85 | | - console.log(totalYears); |
| 76 | +// var total = 0; |
| 77 | +// for(var i = 0; i < inventors.length; i++) { |
| 78 | +// total += inventors[i].passed - inventors[i].year; |
| 79 | +// } |
| 80 | +// console.log(total); |
| 81 | +// |
| 82 | +// var totalYears = inventors.reduce(function(total, inventor) { |
| 83 | +// return total + inventor.passed - inventor.year; |
| 84 | +// }, 0); |
| 85 | +// console.log(totalYears); |
86 | 86 |
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87 | 87 | const totalYear = inventors.reduce( (total, inventor) => { |
88 | 88 | return total + inventor.passed - inventor.year; |
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112 | 112 |
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113 | 113 | // 下面是我在豆瓣里筛选书名里含有 CSS 的书的代码 |
114 | 114 | // https://book.douban.com/tag/web |
115 | | - const cate = document.querySelectorAll('.subject-list h2 a'); |
116 | | - const book = links |
117 | | - .map(link => link.title) |
118 | | - .filter(title => title.includes('CSS')); |
| 115 | +// const links = document.querySelectorAll('.subject-list h2 a'); |
| 116 | +// const book = links |
| 117 | +// .map(link => link.title) |
| 118 | +// .filter(title => title.includes('CSS')); |
119 | 119 |
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120 | 120 |
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121 | 121 | // 7. sort Exercise |
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129 | 129 |
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130 | 130 | // 8. Reduce Exercise |
131 | 131 | // Sum up the instances of each of these |
| 132 | + // 统计各个物品的数量 |
132 | 133 | const data = ['car', 'car', 'truck', 'truck', 'bike', 'walk', 'car', 'van', 'bike', 'walk', 'car', 'van', 'car', 'truck' ]; |
133 | 134 | const reduce = data.reduce( (obj, item) => { |
134 | 135 | if( !obj[item] ) { |
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