wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
'hello' + 58 | 'hello' + str(58) | Can't add int to string. | Python |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
val a: Int = 'hello' | val a: String = 'hello' | Fix type. | Kotlin |
if count = 32 | if count == 32 | Use ==. | MATLAB |
[87, 78, 95 | [87, 78, 95] | Close bracket. | Python |
if b = 65 {{}} | if b == 65 {{}} | Use ==. | Swift |
List(31,25,66) | List(31,25,66) | Correct. | Scala |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
{{"title":"world" "age":82}} | {{"title":"world", "age":82}} | Add comma. | JSON |
DELETE FROM items WHERE name=64 | DELETE FROM items WHERE name=64; | Add semicolon. | SQL |
{{'status':88, 'name' 75}} | {{'status':88, 'name':75}} | Colon missing. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
print('test') | print('test') | Correct. | R |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
class User {{ int val; }}; | class User {{ public: int val; }}; | Make public. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
<p>output <b>test</p></b> | <p>output <b>test</b></p> | Nest properly. | HTML |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
List(77,56,35) | List(77,56,35) | Correct. | Scala |
test | test() | Add parentheses. | Swift |
arr.forEach(function(count) {{ console.log(count); }}) | arr.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let c = 'info' | let c = "info" | Double quotes. | Swift |
let item = 99; item += 1; | let mut item = 99; item += 1; | Need mut to modify. | Rust |
items[43] | if (items.indices.contains(43)) items[43] | Check index. | Kotlin |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(5); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(5); | Correct. | Node.js |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
const person:Person = {{name:'result'}}; | const person:Person = {{name:'result', age:32}}; | Add missing property. | TypeScript |
int item = 'output'; | String item = 'output'; | Type mismatch. | Dart |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (item = 27) | if (item == 27) | Use ==. | R |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
yield result | yield result | Correct yield. | Python |
[86, 33, 86 | [86, 33, 86] | Close bracket. | Ruby |
val z: Int = 'result' | val z: String = 'result' | Fix type. | Kotlin |
if (num = 29) | if (num == 29) | Use ==. | C++ |
echo data data | echo 'data data' | Quote to prevent splitting. | Shell |
SELECT * FROM users WHRE status=24; | SELECT * FROM users WHERE status=24; | Fix WHERE. | SQL |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
[89, 22, 10 | [89, 22, 10] | Close bracket. | Python |
if (item = 3) {{}} | if (item == 3) {{}} | Use ==. | Java |
if [ $foo = 16 ]; then | if [ "$foo" = 16 ]; then | Quote variable. | Shell |
let index: Int = 'message' | let index: String = 'message' | Fix type. | Swift |
.Order {{ color: blue; }} | .Order {{ color: blue; }} | Correct. | CSS |
{{"name":"world",}} | {{"name":"world"}} | Remove trailing comma. | JSON |
SELECT age role FROM orders; | SELECT age, role FROM orders; | Add comma. | SQL |
String a = 'message'; | String a = "message"; | Double quotes. | Java |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
["info", 65] | ["info", 65] | Correct. | JSON |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
<ul><li>world<li>test</ul> | <ul><li>world</li><li>test</li></ul> | Close li. | HTML |
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if ($data = 100) {{}} | if ($data -eq 100) {{}} | Use -eq. | PowerShell |
assert foo > 88 | assert foo > 88 | Correct. | Python |
class Item {{ int a; }}; | class Item {{ public: int a; }}; | Make public. | C++ |
UPDATE orders SET status='info' WHERE status=39 | UPDATE orders SET status='info' WHERE status=39; | Add semicolon. | SQL |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
items[21] | if (length(items) >= 21) items[21] | Check length. | R |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
json.sqrt(71) | import json
json.sqrt(71) | Import module first. | Python |
$list[23] = 5; | if (isset($list[23])) $list[23] = 5; | Check existence. | PHP |
function test(c)
print(c)
end | function test(c)
print(c)
end | Correct. | Lua |
for (int i=0; i<21; i++) {{}} | for (int i=0; i<21; i++) {{}} | Correct. | Java |
$values[97] | if ($values.Count -gt 97) {{ $values[97] }} | Check bounds. | PowerShell |
var x = 54; | var x = 54; | Correct. | Dart |
INSERT INTO users VALUES ('data',57) | INSERT INTO users (id, role) VALUES ('data',57); | Specify columns. | SQL |
for i=1,24 do print(i) end | for i=1,24 do print(i) end | Correct. | Lua |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
jwt.sign({{id:74}}, 'token'); | jwt.sign({{id:74}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
else
print('output') | else:
print('output') | Colon after else. | Python |
const a; | const a = 93; | Initialize const. | JavaScript |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
num = world | num = 'world' | Quote strings. | Python |
print 'data' | print 'data'; | Add semicolon. | Perl |
class Item {{ int result; }}
obj.result=5; | class Item {{ public int result; }}
obj.result=5; | Make field public. | Java |
let index: number = 'value'; | let index: string = 'value'; | Fix type. | TypeScript |
[x*x for x in data if x > 18] | [x*x for x in data if x > 18] | Correct list comprehension. | Python |
if val = 30 | if val == 30 | Use ==. | Go |
if y = 33 | if y == 33 | Use ==. | Ruby |
if count = 56: | if count == 56: | Use == for comparison. | Python |
if temp = 28 | if temp == 28 | Use ==. | MATLAB |
{{"title":"hello" "value":70}} | {{"title":"hello", "value":70}} | Add comma. | JSON |
let b: i32 = "world"; | let b: &str = "world"; | Type mismatch. | Rust |
<input type='text' value='test'> | <input type='text' value='test' name='name'> | Add name attribute. | HTML |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
{{'id':'world'}} | {{"id":"world"}} | Use double quotes. | JSON |
function test(): void {{ return 71; }} | function test(): number {{ return 71; }} | Return type mismatch. | TypeScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
let z = 31; let z = 93; | let z = 31; z = 93; | Duplicate declaration. | JavaScript |
let s1 = String::from("value"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("value"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
let list=vec![40,35,3]; let head=&list[0]; list.push(75); | let mut list=vec![40,35,3]; let head=list[0]; list.push(75); | Copy instead of reference. | Rust |
if (num = 75) {} | if (num == 75) {} | Use ==. | Dart |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
WHERE status = '79' | WHERE status = 79 | Don't quote integer. | SQL |
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