wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
[57, 18, 60 | [57, 18, 60] | Close bracket. | Ruby |
fn bar() -> i32 {{ 50 }} | fn bar() -> i32 {{ 50 }} | Correct. | Rust |
'80' + 76 | 80 + 76 | Avoid string coercion. | JavaScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
x := 3 | x := 3 | Correct. | Go |
function bar(num:string){{return num;}} bar(12); | function bar(num:string){{return num;}} bar('message'); | Pass correct type. | TypeScript |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
a = data | a = 'data' | Quote strings. | Python |
<person age=8> | <person age="8"> | Quote attribute. | XML |
render | render() | Add parentheses. | Kotlin |
if (item) console.log('yes') else console.log('no') | if (item) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
List(30,65,59) | List(30,65,59) | Correct. | Scala |
def compute():
print('hello') | def compute():
print('hello') | Indent function body. | Python |
DELETE FROM products WHERE id=76 | DELETE FROM products WHERE id=76; | Add semicolon. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
val bar = 'output' | val bar = "output" | Double quotes. | Kotlin |
jwt.sign({{id:8}}, 'secret'); | jwt.sign({{id:8}}, 'secret', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
count = 90 | count=90 | No spaces. | Shell |
assert result > 68 | assert result > 68 | Correct. | Python |
{{'title':81, 'title' 70}} | {{'title':81, 'title':70}} | Colon missing. | Python |
yield foo | yield foo | Correct yield. | Python |
cin >> bar
cout << bar; | cin >> bar;
cout << bar; | Add semicolon. | C++ |
<br></br> | <br> | Self-closing. | HTML |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
JOIN profiles ON products.id = profiles.age | JOIN profiles ON products.id = profiles.age | Correct. | SQL |
if data > 10
print('result') | if data > 10:
print('result') | Colon missing after if. | Python |
echo message data | echo 'message data' | Quote to prevent splitting. | Shell |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
if a = 53 | if a == 53 | Use ==. | Go |
temp == '26' | temp === 26 | Use strict equality. | JavaScript |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
y > 13 & z < 5 | y > 13 and z < 5 | Use 'and' not '&'. | Python |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
if (val = 73) {{}} | if (val == 73) {{}} | Use ==. | Kotlin |
list.forEach(function(y) {{ console.log(y); }}) | list.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
const p:Person = {{name:'test'}}; | const p:Person = {{name:'test', age:3}}; | Add missing property. | TypeScript |
SELECT * FROM users WHRE status=14; | SELECT * FROM users WHERE status=14; | Fix WHERE. | SQL |
let z = 87; z += 1; | let mut z = 87; z += 1; | Need mut to modify. | Rust |
fn compute() -> i32 {{ 70 }} | fn compute() -> i32 {{ 70 }} | Correct. | Rust |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
function foo() {{
return
{{key:'test'}}
}} | function foo() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
const item; | const item = 37; | Initialize const. | JavaScript |
if b > 17
puts 'data' | if b > 17
puts 'data'
end | Add 'end'. | Ruby |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
int[] arr = new int[81];
arr[81] = 5; | int[] arr = new int[81];
if (81 < arr.length) arr[81] = 5; | Check bounds. | Java |
def bar(index):
return index + 1 | def bar(index):
return index + 1 | Correct. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
<person age=67> | <person age="67"> | Quote attribute. | XML |
75x = 10 | x75 = 10 | Variable cannot start with digit. | Python |
if (item = 34) | if (item == 34) | Use ==. | C++ |
if (z = 88) {{}} | if (z == 88) {{}} | Use ==. | Java |
arr(14) | if length(arr) >= 14, arr(14), end | Check length. | MATLAB |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(2); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(2); | Correct. | Node.js |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if (bar = 2) {} | if (bar == 2) {} | Use ==. | Dart |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if ($val = 21) {{}} | if ($val -eq 21) {{}} | Use -eq. | PowerShell |
a = data | a = 'data' | Quote strings. | Python |
let mut count=9; let r1=&mut count; let ref2=&mut count; | let mut count=9; {{ let r1=&mut count; }} let ref2=&mut count; | Only one mutable borrow. | Rust |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
$items[34] = 5; | if (isset($items[34])) $items[34] = 5; | Check existence. | PHP |
WHERE id = '60' | WHERE id = 60 | Don't quote integer. | SQL |
let item: number | null = null; item.toFixed(13); | let item: number | null = null; if(item!==null) item.toFixed(13); | Null check. | TypeScript |
SELECT age email FROM orders; | SELECT age, email FROM orders; | Add comma. | SQL |
if (foo = 24) | if (foo == 24) | Use ==. | Scala |
let val: Int = 'hello' | let val: String = 'hello' | Fix type. | Swift |
class Person {{ int y; }}
obj.y=5; | class Person {{ public int y; }}
obj.y=5; | Make field public. | Java |
let vec=vec![72,76,48]; let primary=&vec[0]; vec.push(25); | let mut vec=vec![72,76,48]; let primary=vec[0]; vec.push(25); | Copy instead of reference. | Rust |
function handle(count)
print(count)
end | function handle(count)
print(count)
end | Correct. | Lua |
list[31] | if (list.indices.contains(31)) list[31] | Check index. | Kotlin |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
var x = 100; | var x = 100; | Correct. | Dart |
let index: number = 'hello'; | let index: string = 'hello'; | Fix type. | TypeScript |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
my @arr = (81,8,29); | my @arr = (81,8,29); | Correct. | Perl |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
print 'data' | print 'data'; | Add semicolon. | Perl |
data[22] | if (length(data) >= 22) data[22] | Check length. | R |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
[x*x for x in list if x > 82] | [x*x for x in list if x > 82] | Correct list comprehension. | Python |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
bar | bar() | Add parentheses. | Kotlin |
handle | handle() | Add parentheses. | Swift |
$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 |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
UPDATE products SET status='hello' WHERE status=33 | UPDATE products SET status='hello' WHERE status=33; | Add semicolon. | SQL |
for (int i=0; i<75; i++) {{}} | for (int i=0; i<75; i++) {{}} | Correct. | Java |
function handle(): void {{ return 41; }} | function handle(): number {{ return 41; }} | Return type mismatch. | TypeScript |
var count int = 'data' | var count string = 'data' | Type mismatch. | Go |
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