stringAndArrayMethods
charAt -- returns a new string that contains a character at a specific index. Time complexity O(1) ie let sring - "i love pie" sring.charAt(1) = (space) sring.charAt(4) = v sring.charAt(2) = l
charCodeAt -- returns an integer between 0 and 65535 (code that handles unicode characters-- based on the ASCII) at that specific index. Time complexity O(1) ie let string - "This is string" string.charCodeAt(0) = 84 string.charCodeAt(1) = 104 string.charCodeAt(2) = 105
concat -- method to join two or more string, does not change existing strings but returns a new string containing the text of a joined string. Time complexity of O(n) ie let str1 = 'hello' let str2 = 'world' let result = str1.concat(str2) = 'helloworld' let result = str2.concat(str1) = 'worldhello'
let str3 = 'hello '
let str4 = 'world'
let result = str1.concat(str2) = 'hello world'
let result = str2.concat(str1) = 'worldhello '
includes -- case sensitive method that determines whether it contains specified string/character by returning t or f. Time complexity of O(1) ie let cost = $50.90 console.log(cost.includes($)) = true console.log(cost.includes(.)) = true console.log(cost.includes(%)) = false
let string3= "Just a string" console.log(string3.includes('Script', 5)) = false
indexOf -- method that returns the index of the element that exists in the array or the first occurance of where it is. Time complexity of O(n) ie let str1 = 'finding substring in string' let example2= str1.indexOf('str') console.log(example) = 11
match -- method that searches a string for a match and returns the match as an array object. Time complexity is O(n) **matches against regular expression, if not 'match()' will convert it to a regular expression **. ie let str2 = 'Price: $5 - $15' let result = str2.match(/$\d+/g) console.log(result) = [ '$5', '$15']
repeat -- method that returns a string containing a specified number of copies of string. Time complexity is O(1) ie let str3= 'hello world' console.log(str3.repeat(2)) = 'hello worldhello world'
replace -- method that searches a string for a specified value or regex and returns ndw string where that specified value is/are replaced. Time complexity is O(n) ie let str= 'hello world' let result = str.replace('world', 'mom') = 'hello mom'
search: case sensitive method that searches a string for a specified value and returns the position of the match. Time complexity is O(1). ie let re = /[A-Z]/ let str = 'hi There! How are you?' let index = str.search(re) console.log(index) = 3 --> count by the index after the first cap letter, if doesnt exist it will return (-1)
slice -- method that returns a copy of a sub array between two index, start and end. Time complexity is O(n) ie const users = [ {name:'Luis', age:15}, {name:'Jose', age:18}, {name:'Aaron', age:40} ]; const adults = users.slice(1, users.length) console.log(adults) = (2) [{name: "Jose", age: 18}, {name: "Aaron", age: 40}]
split -- method that splits a string into an array of substrings. Time complexity is O(n) ie let str = 'i like pie' console.log(str.split('') = [ 'i', 'like', 'pie']
substr -- method that extract part of a string, it begins at the character at the specified position and returns specifed number of characters. Time complexity is O(n)
toLowerCase -- method that converts a string to lowercase letters. Time complexity is O(n) ie let str = 'HelLO WoRLd' console.log(str.toLowerCase) = 'hello world'
toUpperCase -- method that converts a string to uppercase letters. Time complexity is O(n) ie let str = 'HelLO WoRLd' console.log(str.toUpperCase) = 'HELLO WORLD'
trim - method that removes whitespace string. Time complexity is O(n) ie let str = 'HelLO WoRLd' console.log(str.trim) = 'HelLOWoRLd'