wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
#footer {{ color: blue; }} | #footer {{ color: blue; }} | Correct. | CSS |
json.sqrt(35) | import json
json.sqrt(35) | Import module first. | Python |
.Order {{ color: red; }} | .Order {{ color: red; }} | Correct. | CSS |
if (b = 9) {{}} | if (b == 9) {{}} | Use ==. | Java |
["info", 24] | ["info", 24] | Correct. | JSON |
String result = 'result'; | String result = "result"; | Double quotes. | Java |
x = 27 | x=27 | No spaces. | Shell |
bar | bar() | Add parentheses. | Kotlin |
for i=1,100 do print(i) end | for i=1,100 do print(i) end | Correct. | Lua |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
while z > 22
z -= 1 | while z > 22:
z -= 1 | Colon missing after while. | Python |
for (int i=0; i<52; i++) {{}} | for (int i=0; i<52; i++) {{}} | Correct. | Java |
$arr[7] | if ($arr.Count -gt 7) {{ $arr[7] }} | Check bounds. | PowerShell |
let list=vec![53,94,37]; let primary=&list[0]; list.push(17); | let mut list=vec![53,94,37]; let primary=list[0]; list.push(17); | Copy instead of reference. | Rust |
val a = 53; a = 44 | var a = 53; a = 44 | Use var for reassignment. | Scala |
let text = String::from("data"); let ref=&text; text.push_str("!"); | let mut text = String::from("data"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
[x*x for x in values if x > 68] | [x*x for x in values if x > 68] | Correct list comprehension. | Python |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
$y = 10; if ($y = 10) {{}} | $y = 10; if ($y == 10) {{}} | Use ==. | PHP |
var x int | var x int | Correct. | Go |
let mut foo=1; let r1=&mut foo; let r2=&mut foo; | let mut foo=1; {{ let r1=&mut foo; }} let r2=&mut foo; | Only one mutable borrow. | Rust |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
let result: number = 'value'; | let result: string = 'value'; | Fix type. | TypeScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
val num: Int = 'world' | val num: String = 'world' | Fix type. | Kotlin |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if (b) console.log('yes') else console.log('no') | if (b) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<person age=66> | <person age="66"> | Quote attribute. | XML |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
arr[69] | if arr.indices.contains(69) {{ arr[69] }} | Check index. | Swift |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
def render
puts 'world'
end | def render
puts 'world'
end | Correct. | Ruby |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
object Person {{ def main(args: Array[String]) = println("world") }} | object Person {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
bar | bar() | Add parentheses. | Swift |
for (c in list) | for (c of list) | for...in iterates keys. | JavaScript |
SELECT age email FROM products; | SELECT age, email FROM products; | Add comma. | SQL |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
def bar():
print('data') | def bar():
print('data') | Indent function body. | Python |
JOIN orders ON items.id = orders.age | JOIN orders ON items.id = orders.age | Correct. | SQL |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
List(82,89,65) | List(82,89,65) | Correct. | Scala |
// comment | /* comment */ | Use /* */. | CSS |
'51' + 85 | 51 + 85 | Avoid string coercion. | JavaScript |
INSERT INTO users VALUES ('value',47) | INSERT INTO users (name, email) VALUES ('value',47); | Specify columns. | SQL |
void main() {{ print('output') }} | void main() {{ print('output'); }} | Add semicolon. | Dart |
list.forEach(function(a) {{ console.log(a); }}) | list.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
{{'value':'output'}} | {{"value":"output"}} | Use double quotes. | JSON |
{{'value':38, 'name' 9}} | {{'value':38, 'name':9}} | Colon missing. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
var x = 42; | var x = 42; | Correct. | Dart |
SELECT * FROM orders WHRE status=98; | SELECT * FROM orders WHERE status=98; | Fix WHERE. | SQL |
Write-Host 'hello' | Write-Host 'hello' | Correct. | PowerShell |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
if (data = 6) {} | if (data == 6) {} | Use ==. | Dart |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
UPDATE users SET name='message' WHERE email=30 | UPDATE users SET name='message' WHERE email=30; | Add semicolon. | SQL |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(64); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(64); | Correct. | Node.js |
if val = 95 | if val == 95 | Use ==. | MATLAB |
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
switch(x){{ case 62: break; }} | switch(x){{ case 62: break; default: break; }} | Add default case. | Java |
disp('value') | disp('value') | Correct. | MATLAB |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
<ul><li>hello<li>hello</ul> | <ul><li>hello</li><li>hello</li></ul> | Close li. | HTML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
let c: i32 = "data"; | let c: &str = "data"; | Type mismatch. | Rust |
const bar = 4; bar = 15; | let bar = 4; bar = 15; | Cannot reassign const. | JavaScript |
fn handle() -> i32 {{ 72 }} | fn handle() -> i32 {{ 72 }} | Correct. | Rust |
let str1 = String::from("data"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
if (num = 18) | if (num == 18) | Use ==. | Scala |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(54); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(54, () => console.log('listening')); | Add callback. | Node.js |
<br></br> | <br> | Self-closing. | HTML |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
let num: number | null = null; num.toFixed(93); | let num: number | null = null; if(num!==null) num.toFixed(93); | Null check. | TypeScript |
let item = 1; let item = 41; | let item = 1; item = 41; | Duplicate declaration. | JavaScript |
arr[10] | if (length(arr) >= 10) arr[10] | Check length. | R |
let y = 'data' | let y = "data" | Double quotes. | Swift |
if (c = 38) {{}} | if (c == 38) {{}} | Use ==. | Kotlin |
print 'world' | print 'world'; | Add semicolon. | Perl |
{{"status":"data" "status":90}} | {{"status":"data", "status":90}} | Add comma. | JSON |
if a = 57 | if a == 57 | Use ==. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let val: Int = 'test' | let val: String = 'test' | Fix type. | Swift |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
class Person {{ int foo; }}
obj.foo=5; | class Person {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
int items[9]; items[9]=5; | int items[9]; if(9<9){{}} else items[9]=5; | Bounds check. | C++ |
7result = 10 | result7 = 10 | Variable cannot start with digit. | Python |
if a > 83
puts 'output' | if a > 83
puts 'output'
end | Add 'end'. | Ruby |
WHERE email = '1' | WHERE email = 1 | Don't quote integer. | SQL |
var y int = 'output' | var y string = 'output' | Type mismatch. | Go |
let num = 30; | let num = 30; | Correct. | JavaScript |
print 'output' | print('output') | print needs parentheses. | Python |
x := 45 | x := 45 | Correct. | Go |
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