exercise level1 complete

solutions/day-01/level1.js

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+// Declare an empty array
+const emptyArray = [];
+
+// Declare an array with more than 5 elements
+const numbersArray = [1, 2, 3, 4, 5, 6, 7];
+
+// Find the length of the array
+const numbersArrayLength = numbersArray.length;
+
+// Get the first, middle, and last items of the array
+const firstItem = numbersArray[0];
+const middleItem = numbersArray[Math.floor(numbersArray.length / 2)];
+const lastItem = numbersArray[numbersArray.length - 1];
+
+// Declare an array with mixed data types
+const mixedDataTypes = [1, 'apple', true, null, { name: 'John' }];
+const mixedDataTypesLength = mixedDataTypes.length;
+
+// Declare an array called itCompanies
+const itCompanies = ['Facebook', 'Google', 'Microsoft', 'Apple', 'IBM', 'Oracle', 'Amazon'];
+
+// Print the array
+console.log(itCompanies);
+
+// Print the number of companies in the array
+const numCompanies = itCompanies.length;
+console.log('Number of companies:', numCompanies);
+
+// Print the first, middle, and last company
+const firstCompany = itCompanies[0];
+const middleCompany = itCompanies[Math.floor(numCompanies / 2)];
+const lastCompany = itCompanies[numCompanies - 1];
+console.log('First company:', firstCompany);
+console.log('Middle company:', middleCompany);
+console.log('Last company:', lastCompany);
+
+// Print out each company
+itCompanies.forEach(company => {
+ console.log(company);
+});
+
+// Change each company name to uppercase one by one and print them out
+itCompanies.forEach((company, index) => {
+ itCompanies[index] = company.toUpperCase();
+ console.log(company);
+});
+
+// Print the array as a sentence
+const sentence = itCompanies.join(', ') + ' are big IT companies.';
+console.log(sentence);
+
+// Check if a certain company exists in the itCompanies array
+const searchCompany = 'Microsoft';
+if (itCompanies.includes(searchCompany)) {
+ console.log(searchCompany + ' exists in the array.');
+} else {
+ console.log(searchCompany + ' is not found in the array.');
+}
+
+// Filter out companies with more than one 'o'
+const filteredCompanies = itCompanies.filter(company => company.toLowerCase().split('o').length - 1 <= 1);
+
+// Sort the array
+itCompanies.sort();
+
+// Reverse the array
+itCompanies.reverse();
+
+// Slice out the first 3 companies
+const firstThreeCompanies = itCompanies.slice(0, 3);
+
+// Slice out the last 3 companies
+const lastThreeCompanies = itCompanies.slice(-3);
+
+// Slice out the middle IT company
+const middleCompanyIndex = Math.floor(numCompanies / 2);
+const middleITCompany = itCompanies.slice(middleCompanyIndex, middleCompanyIndex + 1);
+
+// Remove the first IT company
+itCompanies.shift();
+
+// Remove the middle IT company
+itCompanies.splice(middleCompanyIndex, 1);
+
+// Remove the last IT company
+itCompanies.pop();
+
+// Remove all IT companies
+itCompanies.length = 0;