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https://github.com/apollo-level2-web-dev/practice-tasks-2-solutions
https://github.com/apollo-level2-web-dev/practice-tasks-2-solutions
Last synced: 24 days ago
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- Host: GitHub
- URL: https://github.com/apollo-level2-web-dev/practice-tasks-2-solutions
- Owner: Apollo-Level2-Web-Dev
- Created: 2024-05-12T10:24:38.000Z (7 months ago)
- Default Branch: main
- Last Pushed: 2024-05-13T15:49:33.000Z (7 months ago)
- Last Synced: 2024-05-14T12:40:41.019Z (7 months ago)
- Size: 3.91 KB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# practice-tasks-2-solutions
## Problem Statements
### 1. Retrieve the count of individuals who are active (`isActive: true`) for each gender.
```javascript
db.collection.aggregate([
{ $match: { isActive: true } },
{
$group: {
_id: "$gender",
count: { $sum: 1 },
},
},
]);
```
### 2. Retrieve the names and email addresses of individuals who are active (isActive: true) and have a favorite fruit of "banana".
```javascript
db.collection.aggregate([
{ $match: { isActive: true, favoriteFruit: "banana" } },
]);
```
### 3. Find the average age of individuals for each favorite fruit, then sort the results in descending order of average age.
```javascript
db.collection.aggregate([
{
$group: {
_id: "$favoriteFruit",
averageAge: { $avg: "$age" },
},
},
{
$sort: { averageAge: -1 },
},
]);
```
### 4. Retrieve a list of unique friend names for individuals who have at least one friend, and include only the friends with names starting with the letter "W".
```javascript
db.collection.aggregate([
{ $unwind: "$friends" },
{
$match: {
"friends.name": /^W/,
},
},
{
$group: {
_id: "$_id",
uniqueFriends: { $addToSet: "$friends.name" },
},
},
]);
```
#### 5. Use $facet to separate individuals into two facets based on their age: those below 30 and those above 30. Then, within each facet, bucket the individuals into age ranges and sort them by age within each bucket.
```javascript
db.collection.aggregate([
{
$facet: {
below30: [
{ $match: { age: { $lt: 30 } } },
{
$bucket: {
groupBy: "$age",
boundaries: [20, 25, 30],
default: "Other",
output: {
names: { $push: "$name" },
},
},
},
{
$sort: {age: 1}
}
],
above30: [
{ $match: { age: { $gte: 30 } } },
{
$bucket: {
groupBy: "$age",
boundaries: [30, 35, 40],
default: "Other",
output: {
names: { $push: "$name" },
},
},
},
],
},
},
{
$sort: {age: 1}
}
]);
```
### 6.Calculate the total balance of individuals for each company and display the company name along with the total balance. Limit the result to show only the top two companies with the highest total balance.
```javascript
db.collection.aggregate([
{
$group: {
_id: "$company",
totalBalance: { $sum: { $toDouble: { $substr: ["$balance", 1, -1] } } },
},
},
{
$sort: { totalBalance: -1 },
},
{
$limit: 2,
},
]);
```