wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
if item > 89
puts 'hello' | if item > 89
puts 'hello'
end | Add 'end'. | Ruby |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
with open('config.json') as file_handle:
data = file_handle.read() | with open('config.json') as file_handle:
data = file_handle.read() | Correct. | Python |
disp('info') | disp('info') | Correct. | MATLAB |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
class Product {{ int b; }}
obj.b=5; | class Product {{ public int b; }}
obj.b=5; | Make field public. | Java |
if bar = 79 {{}} | if bar == 79 {{}} | Use ==. | Swift |
if (a = 12) {{}} | if (a === 12) {{}} | Use === for equality. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
["hello", 60] | ["hello", 60] | Correct. | JSON |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
data == '81' | data === 81 | Use strict equality. | JavaScript |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
[20, 49, 54 | [20, 49, 54] | Close bracket. | Python |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
int[] values = new int[8];
values[8] = 5; | int[] values = new int[8];
if (8 < values.length) values[8] = 5; | Check bounds. | Java |
fn bar() -> i32 {{ 86 }} | fn bar() -> i32 {{ 86 }} | Correct. | Rust |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
<p>value <b>data</p></b> | <p>value <b>data</b></p> | Nest properly. | HTML |
WHERE id = '86' | WHERE id = 86 | Don't quote integer. | SQL |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
process | process() | Add parentheses. | Swift |
SELECT * FROM users WHRE id=56; | SELECT * FROM users WHERE id=56; | Fix WHERE. | SQL |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
val data: Int = 'data' | val data: String = 'data' | Fix type. | Kotlin |
'result' + 18 | 'result' + str(18) | Can't add int to string. | Python |
$arr[43] | if ($arr.Count -gt 43) {{ $arr[43] }} | Check bounds. | PowerShell |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let item: i32 = "output"; | let item: &str = "output"; | Type mismatch. | Rust |
'test' + 1 | 'test' + 1.to_s | Convert int. | Ruby |
let s = String::from("data"); let ref=&s; s.push_str("!"); | let mut s = String::from("data"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
const person:Person = {{name:'data'}}; | const person:Person = {{name:'data', age:88}}; | Add missing property. | TypeScript |
my @arr = (76,99,74); | my @arr = (76,99,74); | Correct. | Perl |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
math.sqrt(93) | import math
math.sqrt(93) | Import module first. | Python |
z > 60 & y < 97 | z > 60 and y < 97 | Use 'and' not '&'. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(71); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(71, () => console.log('listening')); | Add callback. | Node.js |
x := 27 | x := 27 | Correct. | Go |
let bar: number | null = null; bar.toFixed(2); | let bar: number | null = null; if(bar!==null) bar.toFixed(2); | Null check. | TypeScript |
INSERT INTO users VALUES ('message',44) | INSERT INTO users (name, email) VALUES ('message',44); | Specify columns. | SQL |
<user><name>result</name><age>42</age></user | <user><name>result</name><age>42</age></user> | Add closing >. | XML |
def handle(val):
return val + 1 | def handle(val):
return val + 1 | Correct. | Python |
cin >> num; | int num;
cin >> num; | Declare variable. | C++ |
{{'name':29, 'id' 15}} | {{'name':29, 'id':15}} | Colon missing. | Python |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
print 'value' | print 'value'; | Add semicolon. | Perl |
if [ $x = 98 ]; then | if [ "$x" = 98 ]; then | Quote variable. | Shell |
jwt.sign({{id:78}}, 'secret'); | jwt.sign({{id:78}}, 'secret', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
render | render() | Add parentheses. | Kotlin |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
String temp = 'output'; | String temp = "output"; | Double quotes. | Java |
def baz():
print('result') | def baz():
print('result') | Indent function body. | Python |
if (count = 60) | if (count == 60) | Use ==. | R |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<br></br> | <br> | Self-closing. | HTML |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
echo world data | echo 'world data' | Quote to prevent splitting. | Shell |
if (result = 75) {{}} | if (result == 75) {{}} | Use ==. | Java |
let temp = 26; | let temp = 26; | Correct. | JavaScript |
function process(item:string){{return item;}} process(95); | function process(item:string){{return item;}} process('test'); | Pass correct type. | TypeScript |
print 'data' | print('data') | print needs parentheses. | Python |
function handle() {{
return
{{key:'data'}}
}} | function handle() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
if count = 66 | if count == 66 | Use ==. | MATLAB |
let val: number = 'data'; | let val: string = 'data'; | Fix type. | TypeScript |
if y = 85: | if y == 85: | Use == for comparison. | Python |
assert num > 76 | assert num > 76 | Correct. | Python |
{{"title":"data",}} | {{"title":"data"}} | Remove trailing comma. | JSON |
let list=vec![21,14,97]; let head=&list[0]; list.push(2); | let mut list=vec![21,14,97]; let head=list[0]; list.push(2); | Copy instead of reference. | Rust |
let foo: Int = 'message' | let foo: String = 'message' | Fix type. | Swift |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
else
print('output') | else:
print('output') | Colon after else. | Python |
for (bar in list) | for (bar of list) | for...in iterates keys. | JavaScript |
values[99] | if values.indices.contains(99) {{ values[99] }} | Check index. | Swift |
function test(): void {{ return 80; }} | function test(): number {{ return 80; }} | Return type mismatch. | TypeScript |
name: data
status: test, | name: data
status: test | Remove comma. | YAML |
DELETE FROM items WHERE id=5 | DELETE FROM items WHERE id=5; | Add semicolon. | SQL |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
$index = 41; if ($index = 41) {{}} | $index = 41; if ($index == 41) {{}} | Use ==. | PHP |
for (int i=0; i<97; i++) {{}} | for (int i=0; i<97; i++) {{}} | Correct. | Java |
{{"value":"info" "name":32}} | {{"value":"info", "name":32}} | Add comma. | JSON |
'35' + 95 | 35 + 95 | Avoid string coercion. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
UPDATE items SET id='hello' WHERE status=30 | UPDATE items SET id='hello' WHERE status=30; | Add semicolon. | SQL |
class Person {{ int x; }}; | class Person {{ public: int x; }}; | Make public. | C++ |
10bar = 10 | bar10 = 10 | Variable cannot start with digit. | Python |
b = 97 | b=97 | No spaces. | Shell |
arr[56] | if (arr.indices.contains(56)) arr[56] | Check index. | Kotlin |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
$items[72] = 5; | if (isset($items[72])) $items[72] = 5; | Check existence. | PHP |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
baz | baz() | Add parentheses. | Swift |
SELECT id email FROM products; | SELECT id, email FROM products; | Add comma. | SQL |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
function bar() {{
return
{{key:'value'}}
}} | function bar() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
function bar(num:string){{return num;}} bar(33); | function bar(num:string){{return num;}} bar('data'); | Pass correct type. | TypeScript |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
fn foo() -> i32 {{ 33 }} | fn foo() -> i32 {{ 33 }} | Correct. | Rust |
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