recursion

问题 I am trying to understand this recursion. I know how recursion works in factorial function but when it gets to this complex recursion like this I am confused. The most confusing part to me is this code str.split('').map( (char, i) => permutations( str.substr(0, i) + str.substr(i + 1) )map( p => char + p)) First, with "abc" , say, it will split into ["a","b","c"] and go through the map function, then go through the second map function to wrap each return with a , b , c , respectively. However,

问题 I am trying to understand this recursion. I know how recursion works in factorial function but when it gets to this complex recursion like this I am confused. The most confusing part to me is this code str.split('').map( (char, i) => permutations( str.substr(0, i) + str.substr(i + 1) )map( p => char + p)) First, with "abc" , say, it will split into ["a","b","c"] and go through the map function, then go through the second map function to wrap each return with a , b , c , respectively. However,

问题 UPDATED SCRIPT Here is an updated script I am working on: function recursive(data, append_name) { for (parent_key in data) { var dim_type = data[parent_key]["type"]; var dim_label = ""; var dim_name = data[parent_key]["name"]; if (typeof(data[parent_key]["label"])=="object") { dim_label = data[parent_key]["label"]["english"]; } else { dim_label = data[parent_key]["label"]; } for (child_key in data[parent_key]["children"]){ //console.log(data[parent_key]["children"][child_key]) var child_label

问题 UPDATED SCRIPT Here is an updated script I am working on: function recursive(data, append_name) { for (parent_key in data) { var dim_type = data[parent_key]["type"]; var dim_label = ""; var dim_name = data[parent_key]["name"]; if (typeof(data[parent_key]["label"])=="object") { dim_label = data[parent_key]["label"]["english"]; } else { dim_label = data[parent_key]["label"]; } for (child_key in data[parent_key]["children"]){ //console.log(data[parent_key]["children"][child_key]) var child_label

问题 I have a simple html structure that I need to traverse. For some reason my recursive function returns 'undefined' on any nested nodes, but not for parent nodes. Unfortunately this needs to be native js, no jQuery for this one. Thanks! HTML: <div id="container"> <div id="head"> <span id="left"><</span> <span id="right">></span> </div> </div> Script: var h = hasId(container, 'head'); var l = hasId(container, 'left'); var r = hasId(container, 'right'); console.log(h + " : " + r + " : " + l); //

问题 I have a simple html structure that I need to traverse. For some reason my recursive function returns 'undefined' on any nested nodes, but not for parent nodes. Unfortunately this needs to be native js, no jQuery for this one. Thanks! HTML: <div id="container"> <div id="head"> <span id="left"><</span> <span id="right">></span> </div> </div> Script: var h = hasId(container, 'head'); var l = hasId(container, 'left'); var r = hasId(container, 'right'); console.log(h + " : " + r + " : " + l); //

问题 I have a simple html structure that I need to traverse. For some reason my recursive function returns 'undefined' on any nested nodes, but not for parent nodes. Unfortunately this needs to be native js, no jQuery for this one. Thanks! HTML: <div id="container"> <div id="head"> <span id="left"><</span> <span id="right">></span> </div> </div> Script: var h = hasId(container, 'head'); var l = hasId(container, 'left'); var r = hasId(container, 'right'); console.log(h + " : " + r + " : " + l); //

问题 I have this set of (Greek) strings: ἸἼΙἹἽ, ῇηἤήῃὴῆἡἠἢᾖἥἣῄἦᾗᾐἧᾔᾑ, σς, οὸόὀὄὅὂ, ὺὖυῦύὐὑὔΰϋὕὗὓὒῢ I'd like to find all possible permutations of the characters in these 5 strings. For example, Ἰῇσοὺ, Ἰῇσοὖ, Ἰῇσου, etc. I know it should involve recursion since the number of strings is not fixed but I'm a beginner and I'm completely dumbfounded by recursion. I did the following in Python and it does give me all combinations of the characters in each string. But I need the 'ἸἼΙἹἽ' to always come

问题 I have this set of (Greek) strings: ἸἼΙἹἽ, ῇηἤήῃὴῆἡἠἢᾖἥἣῄἦᾗᾐἧᾔᾑ, σς, οὸόὀὄὅὂ, ὺὖυῦύὐὑὔΰϋὕὗὓὒῢ I'd like to find all possible permutations of the characters in these 5 strings. For example, Ἰῇσοὺ, Ἰῇσοὖ, Ἰῇσου, etc. I know it should involve recursion since the number of strings is not fixed but I'm a beginner and I'm completely dumbfounded by recursion. I did the following in Python and it does give me all combinations of the characters in each string. But I need the 'ἸἼΙἹἽ' to always come

问题 I have following json I am trying to validate using @hapi/Joi 16+. It largely works up to 3 levels. But after that it wouldn't validate the alternative files . folder schema get validated fine. I am hoping for optimised solution that would validate deep nested array. In here ONLY folders suppose to have optional children . Files schema should NOT have children . Hence I am using alternatives. const data = [{ id: '1', //UUID type: 'folder', children: [{ id: '2', //UUID type: 'folder', children