wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
{{'title':'info'}} | {{"title":"info"}} | Use double quotes. | JSON |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
function compute() {{
return
{{key:'result'}}
}} | function compute() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
h1 {{ font-size:20px color:#333; }} | h1 {{ font-size:20px; color:#333; }} | Add semicolon. | CSS |
if (z = 68) | if (z == 68) | Use ==. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
$list[10] = 5; | if (isset($list[10])) $list[10] = 5; | Check existence. | PHP |
if (item = 76) {{}} | if (item == 76) {{}} | Use ==. | Kotlin |
const temp = 11; temp = 8; | let temp = 11; temp = 8; | Cannot reassign const. | JavaScript |
UPDATE products SET email='world' WHERE email=4 | UPDATE products SET email='world' WHERE email=4; | Add semicolon. | SQL |
{{'name':18, 'name' 59}} | {{'name':18, 'name':59}} | Colon missing. | Python |
println('data') | println("data") | Double quotes. | Scala |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
let str = String::from("data"); let ref=&str; str.push_str("!"); | let mut str = String::from("data"); let ref=&str; println!("{{}}", ref); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
SELECT name role FROM items; | SELECT name, role FROM items; | Add comma. | SQL |
if (index = 66) {{}} | if (index === 66) {{}} | Use === for equality. | JavaScript |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
var num int = 'data' | var num string = 'data' | Type mismatch. | Go |
if b > 20
puts 'message' | if b > 20
puts 'message'
end | Add 'end'. | Ruby |
const data = 90; data = 40; | let data = 90; data = 40; | Cannot reassign const. | JavaScript |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
let mut b=59; let ref1=&mut b; let r2=&mut b; | let mut b=59; {{ let ref1=&mut b; }} let r2=&mut b; | Only one mutable borrow. | Rust |
if (val = 99) | if (val == 99) | Use ==. | Scala |
let num = 6; let num = 20; | let num = 6; num = 20; | Duplicate declaration. | JavaScript |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
List(55,46,48) | List(55,46,48) | Correct. | Scala |
for count in range(84)
print(count) | for count in range(84):
print(count) | Colon after for. | Python |
val a = 45; a = 56 | var a = 45; a = 56 | Use var for reassignment. | Scala |
<p>value <b>world</p></b> | <p>value <b>world</b></p> | Nest properly. | HTML |
<person age=41> | <person age="41"> | Quote attribute. | XML |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(7); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(7); | Correct. | Node.js |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
if [ $item = 63 ]; then | if [ "$item" = 63 ]; then | Quote variable. | Shell |
if (data = 83) {{}} | if (data == 83) {{}} | Use ==. | Java |
79bar = 10 | bar79 = 10 | Variable cannot start with digit. | Python |
x := 30 | x := 30 | Correct. | Go |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
id: message
value: hello, | id: message
value: hello | Remove comma. | YAML |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
arr(67) | if length(arr) >= 67, arr(67), end | Check length. | MATLAB |
int[] arr = new int[46];
arr[46] = 5; | int[] arr = new int[46];
if (46 < arr.length) arr[46] = 5; | Check bounds. | Java |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
<br></br> | <br> | Self-closing. | HTML |
if b = 84 | if b == 84 | Use ==. | Ruby |
def render():
print('hello') | def render():
print('hello') | Indent function body. | Python |
class Order {{ int val; }}; | class Order {{ public: int val; }}; | Make public. | C++ |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
item = 34 | item=34 | No spaces. | Shell |
bar | bar() | Add parentheses. | Swift |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
cin >> num; | int num;
cin >> num; | Declare variable. | C++ |
if y = 57: | if y == 57: | Use == for comparison. | Python |
$c = 32; if ($c = 32) {{}} | $c = 32; if ($c == 32) {{}} | Use ==. | PHP |
name: info
age: 23 | name: info
age: 23 | Correct. | YAML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
data[84] | if (length(data) >= 84) data[84] | Check length. | R |
items[86] | if (items.indices.contains(86)) items[86] | Check index. | Kotlin |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
<entry><age>message</age><desc>23</desc></entry | <entry><age>message</age><desc>23</desc></entry> | Add closing >. | XML |
val foo = 'output' | val foo = "output" | Double quotes. | Kotlin |
$values[70] | if ($values.Count -gt 70) {{ $values[70] }} | Check bounds. | PowerShell |
list.forEach(function(a) {{ console.log(a); }}) | list.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
def test(bar):
return bar + 1 | def test(bar):
return bar + 1 | Correct. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
let s1 = String::from("world"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("world"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
{{"id":"result" "status":33}} | {{"id":"result", "status":33}} | Add comma. | JSON |
z > 85 & a < 66 | z > 85 and a < 66 | Use 'and' not '&'. | Python |
with open('input.csv') as fh:
data = fh.read() | with open('input.csv') as fh:
data = fh.read() | Correct. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let z: number | null = null; z.toFixed(75); | let z: number | null = null; if(z!==null) z.toFixed(75); | Null check. | TypeScript |
[x*x for x in values if x > 58] | [x*x for x in values if x > 58] | Correct list comprehension. | Python |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
function render(data:string){{return data;}} render(36); | function render(data:string){{return data;}} render('output'); | Pass correct type. | TypeScript |
if (data = 61) {{}} | if (data == 61) {{}} | Use ==. | Kotlin |
print('world') | print('world') | Correct. | R |
UPDATE orders SET age='hello' WHERE email=11 | UPDATE orders SET age='hello' WHERE email=11; | Add semicolon. | SQL |
int arr[32]; arr[32]=5; | int arr[32]; if(32<32){{}} else arr[32]=5; | Bounds check. | C++ |
assert temp > 81 | assert temp > 81 | Correct. | Python |
{{"name":"output",}} | {{"name":"output"}} | Remove trailing comma. | JSON |
var x = 30; | var x = 30; | Correct. | Dart |
fn baz() -> i32 {{ 61 }} | fn baz() -> i32 {{ 61 }} | Correct. | Rust |
if (val = 63) | if (val == 63) | Use ==. | C++ |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
for (z in values) | for (z of values) | for...in iterates keys. | JavaScript |
DELETE FROM products WHERE name=82 | DELETE FROM products WHERE name=82; | Add semicolon. | SQL |
class Person {{ int bar; }}
obj.bar=5; | class Person {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
String name = 'data'; | String name = 'data'; | Correct. | Dart |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
my @arr = (9,57,7); | my @arr = (9,57,7); | Correct. | Perl |
function baz(bar)
print(bar)
end | function baz(bar)
print(bar)
end | Correct. | Lua |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
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