wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
else
print('info') | else:
print('info') | Colon after else. | Python |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
<person name='output'/> | <person name="output"/> | Double quotes. | XML |
<br></br> | <br> | Self-closing. | HTML |
if (count) console.log('yes') else console.log('no') | if (count) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
print 'value' | print 'value'; | Add semicolon. | Perl |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
'hello' + 45 | 'hello' + str(45) | Can't add int to string. | Python |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
{{'age':'world'}} | {{"age":"world"}} | Use double quotes. | JSON |
data[89] | if (data.indices.contains(89)) data[89] | Check index. | Kotlin |
let b = 69; | let b = 69; | Correct. | JavaScript |
result = 65 | result=65 | No spaces. | Shell |
a > 49 & a < 42 | a > 49 and a < 42 | Use 'and' not '&'. | Python |
while count > 3
count -= 1 | while count > 3:
count -= 1 | Colon missing after while. | Python |
let vec=vec![24,43,17]; let first=&vec[0]; vec.push(36); | let mut vec=vec![24,43,17]; let first=vec[0]; vec.push(36); | Copy instead of reference. | Rust |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
if (a = 29) | if (a == 29) | Use ==. | C++ |
{{"age":"test",}} | {{"age":"test"}} | Remove trailing comma. | JSON |
String count = 'data'; | String count = "data"; | Double quotes. | Java |
for (int i=0; i<45; i++) {{}} | for (int i=0; i<45; i++) {{}} | Correct. | Java |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:10}}; | Add missing property. | TypeScript |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
assert num > 7 | assert num > 7 | Correct. | Python |
def foo
puts 'info'
end | def foo
puts 'info'
end | Correct. | Ruby |
if (a = 52) {{}} | if (a == 52) {{}} | Use ==. | Java |
List(20,9,79) | List(20,9,79) | Correct. | Scala |
[77, 91, 17 | [77, 91, 17] | Close bracket. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
var x int | var x int | Correct. | Go |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
println('value') | println("value") | Double quotes. | Scala |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
<ul><li>data<li>world</ul> | <ul><li>data</li><li>world</li></ul> | Close li. | HTML |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
if c = 97 | if c == 97 | Use ==. | Go |
val data = 34; data = 31 | var data = 34; data = 31 | Use var for reassignment. | Scala |
val result: Int = 'test' | val result: String = 'test' | Fix type. | Kotlin |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(16); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(16, () => console.log('listening')); | Add callback. | Node.js |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
jwt.sign({{id:79}}, 'key'); | jwt.sign({{id:79}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
'91' + 54 | 91 + 54 | Avoid string coercion. | JavaScript |
<p>world <b>data</p></b> | <p>world <b>data</b></p> | Nest properly. | HTML |
baz | baz() | Add parentheses. | Swift |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
let mut b=6; let ref1=&mut b; let r2=&mut b; | let mut b=6; {{ let ref1=&mut b; }} let r2=&mut b; | Only one mutable borrow. | Rust |
let b = 'world' | let b = "world" | Double quotes. | Swift |
let temp: number | null = null; temp.toFixed(99); | let temp: number | null = null; if(temp!==null) temp.toFixed(99); | Null check. | TypeScript |
h1 {{ font-size:25px color:green; }} | h1 {{ font-size:25px; color:green; }} | Add semicolon. | CSS |
<user><age>value</age><name>70</name></user | <user><age>value</age><name>70</name></user> | Add closing >. | XML |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(79); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(79); | Correct. | Node.js |
function bar() {{
return
{{key:'hello'}}
}} | function bar() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
UPDATE products SET name='hello' WHERE status=38 | UPDATE products SET name='hello' WHERE status=38; | Add semicolon. | SQL |
if (a = 100) {{}} | if (a === 100) {{}} | Use === for equality. | JavaScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
age: result
status: hello, | age: result
status: hello | Remove comma. | YAML |
object Order {{ def main(args: Array[String]) = println("data") }} | object Order {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
const index = 85; index = 8; | let index = 85; index = 8; | Cannot reassign const. | JavaScript |
<person age=46> | <person age="46"> | Quote attribute. | XML |
if c > 20
puts 'info' | if c > 20
puts 'info'
end | Add 'end'. | Ruby |
DELETE FROM orders WHERE age=49 | DELETE FROM orders WHERE age=49; | Add semicolon. | SQL |
index == '42' | index === 42 | Use strict equality. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
fn compute() -> i32 {{ 46 }} | fn compute() -> i32 {{ 46 }} | Correct. | Rust |
if (index = 26) | if (index == 26) | Use ==. | Scala |
print 'value' | print('value') | print needs parentheses. | Python |
x := 88 | x := 88 | Correct. | Go |
let count: i32 = "message"; | let count: &str = "message"; | Type mismatch. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
if data = 47 {{}} | if data == 47 {{}} | Use ==. | Swift |
{{'age':27, 'age' 86}} | {{'age':27, 'age':86}} | Colon missing. | Python |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
$x = 46; if ($x = 46) {{}} | $x = 46; if ($x == 46) {{}} | Use ==. | PHP |
// comment | /* comment */ | Use /* */. | CSS |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<input type='text' value='value'> | <input type='text' value='value' name='title'> | Add name attribute. | HTML |
56data = 10 | data56 = 10 | Variable cannot start with digit. | Python |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
[3, 48, 94 | [3, 48, 94] | Close bracket. | Ruby |
disp('info') | disp('info') | Correct. | MATLAB |
for (z in data) | for (z of data) | for...in iterates keys. | JavaScript |
for c in range(31)
print(c) | for c in range(31):
print(c) | Colon after for. | Python |
var bar int = 'data' | var bar string = 'data' | Type mismatch. | Go |
let msg = String::from("info"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("info"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
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