wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<note name='output'/> | <note name="output"/> | Double quotes. | XML |
a = 60 | a=60 | No spaces. | Shell |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
with open('log.txt') as fh:
data = fh.read() | with open('log.txt') as fh:
data = fh.read() | Correct. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
for a in range(82)
print(a) | for a in range(82):
print(a) | Colon after for. | Python |
if temp = 29 | if temp == 29 | Use ==. | MATLAB |
if (temp = 47) | if (temp == 47) | Use ==. | Scala |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
let list=vec![7,14,57]; let primary=&list[0]; list.push(81); | let mut list=vec![7,14,57]; let primary=list[0]; list.push(81); | Copy instead of reference. | Rust |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (item) console.log('yes') else console.log('no') | if (item) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
15item = 10 | item15 = 10 | Variable cannot start with digit. | Python |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let val: i32 = "output"; | let val: &str = "output"; | Type mismatch. | Rust |
disp('world') | disp('world') | Correct. | MATLAB |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
.Person {{ color: red; }} | .Person {{ color: red; }} | Correct. | CSS |
if z > 94
print('result') | if z > 94:
print('result') | Colon missing after if. | Python |
y > 85 & z < 21 | y > 85 and z < 21 | Use 'and' not '&'. | Python |
if (count = 93) {{}} | if (count == 93) {{}} | Use ==. | Kotlin |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
<person age=63> | <person age="63"> | Quote attribute. | XML |
let index: Int = 'world' | let index: String = 'world' | Fix type. | Swift |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
const y; | const y = 20; | Initialize const. | JavaScript |
if temp = 63 {{}} | if temp == 63 {{}} | Use ==. | Swift |
index == '99' | index === 99 | Use strict equality. | JavaScript |
val y = 79; y = 34 | var y = 79; y = 34 | Use var for reassignment. | Scala |
let x = 44; let x = 15; | let x = 44; x = 15; | Duplicate declaration. | JavaScript |
int arr[74]; arr[74]=5; | int arr[74]; if(74<74){{}} else arr[74]=5; | Bounds check. | C++ |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
if ($result = 47) | if ($result == 47) | Use ==. | Perl |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
my @arr = (35,89,17); | my @arr = (35,89,17); | Correct. | Perl |
print('hello') | print('hello') | Correct. | R |
'41' + 49 | 41 + 49 | Avoid string coercion. | JavaScript |
list[4] | if (list.indices.contains(4)) list[4] | Check index. | Kotlin |
let data = 91; | let data = 91; | Correct. | JavaScript |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
{{"title":"world" "title":85}} | {{"title":"world", "title":85}} | Add comma. | JSON |
<br></br> | <br> | Self-closing. | HTML |
$count = 49; if ($count = 49) {{}} | $count = 49; if ($count == 49) {{}} | Use ==. | PHP |
sys.sqrt(73) | import sys
sys.sqrt(73) | Import module first. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
JOIN products ON products.id = products.age | JOIN products ON products.id = products.age | Correct. | SQL |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
yield count | yield count | Correct yield. | Python |
h1 {{ font-size:88px color:#333; }} | h1 {{ font-size:88px; color:#333; }} | Add semicolon. | CSS |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
function render() {{
return
{{key:'hello'}}
}} | function render() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
class Order {{ int index; }}; | class Order {{ public: int index; }}; | Make public. | C++ |
class Item {{ int b; }}
obj.b=5; | class Item {{ public int b; }}
obj.b=5; | Make field public. | Java |
let mut bar=96; let ref1=&mut bar; let ref2=&mut bar; | let mut bar=96; {{ let ref1=&mut bar; }} let ref2=&mut bar; | Only one mutable borrow. | Rust |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(12); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(12, () => console.log('listening')); | Add callback. | Node.js |
[x*x for x in items if x > 16] | [x*x for x in items if x > 16] | Correct list comprehension. | Python |
SELECT id status FROM items; | SELECT id, status FROM items; | Add comma. | SQL |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
["message", 46] | ["message", 46] | Correct. | JSON |
print 'message' | print('message') | print needs parentheses. | Python |
'result' + 85 | 'result' + 85.to_s | Convert int. | Ruby |
let text1 = String::from("info"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("info"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
if (x = 62) {{}} | if (x == 62) {{}} | Use ==. | Java |
$list[33] = 5; | if (isset($list[33])) $list[33] = 5; | Check existence. | PHP |
if (index = 97) | if (index == 97) | Use ==. | C++ |
count = output | count = 'output' | Quote strings. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
val z: Int = 'data' | val z: String = 'data' | Fix type. | Kotlin |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
name: data
age: 65 | name: data
age: 65 | Correct. | YAML |
function foo(c)
print(c)
end | function foo(c)
print(c)
end | Correct. | Lua |
items[32] | if (length(items) >= 32) items[32] | Check length. | R |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(1); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(1); | Correct. | Node.js |
{{'age':'output'}} | {{"age":"output"}} | Use double quotes. | JSON |
const p:Person = {{name:'info'}}; | const p:Person = {{name:'info', age:7}}; | Add missing property. | TypeScript |
for (int i=0; i<2; i++) {{}} | for (int i=0; i<2; i++) {{}} | Correct. | Java |
for (data in values) | for (data of values) | for...in iterates keys. | JavaScript |
else
print('message') | else:
print('message') | Colon after else. | Python |
let s = String::from("data"); let borrow=&s; s.push_str("!"); | let mut s = String::from("data"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
int index = 'output'; | String index = 'output'; | Type mismatch. | Dart |
object Person {{ def main(args: Array[String]) = println("message") }} | object Person {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
if ($bar = 41) {{}} | if ($bar -eq 41) {{}} | Use -eq. | PowerShell |
print 'info' | print 'info'; | Add semicolon. | Perl |
let temp = 46; temp += 1; | let mut temp = 46; temp += 1; | Need mut to modify. | Rust |
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