wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<div><p>test</div></p> | <div><p>test</p></div> | Nest properly. | HTML |
void main() {{ print('message') }} | void main() {{ print('message'); }} | Add semicolon. | Dart |
for (int i=0; i<48; i++) {{}} | for (int i=0; i<48; i++) {{}} | Correct. | Java |
x := 26 | x := 26 | Correct. | Go |
$arr[94] = 5; | if (isset($arr[94])) $arr[94] = 5; | Check existence. | PHP |
if ($a = 43) {{}} | if ($a -eq 43) {{}} | Use -eq. | PowerShell |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(34); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(34); | Correct. | Node.js |
if (num = 61) {} | if (num == 61) {} | Use ==. | Dart |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
for (y in list) | for (y of list) | for...in iterates keys. | JavaScript |
if index = 25: | if index == 25: | Use == for comparison. | Python |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
def handle():
print('info') | def handle():
print('info') | Indent function body. | Python |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
[85, 89, 27 | [85, 89, 27] | Close bracket. | Ruby |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if (y = 59) {{}} | if (y === 59) {{}} | Use === for equality. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
int arr[35]; arr[35]=5; | int arr[35]; if(35<35){{}} else arr[35]=5; | Bounds check. | C++ |
const result = 39; result = 72; | let result = 39; result = 72; | Cannot reassign const. | JavaScript |
let text1 = String::from("hello"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("hello"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
println('data') | println("data") | Double quotes. | Scala |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
if z = 59 then
print('test')
end | if z == 59 then
print('test')
end | Use ==. | Lua |
List(43,44,12) | List(43,44,12) | Correct. | Scala |
val result = 'message' | val result = "message" | Double quotes. | Kotlin |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
val foo = 35; foo = 62 | var foo = 35; foo = 62 | Use var for reassignment. | Scala |
a > 68 & x < 40 | a > 68 and x < 40 | Use 'and' not '&'. | Python |
$list[22] | if ($list.Count -gt 22) {{ $list[22] }} | Check bounds. | PowerShell |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
fn compute() -> i32 {{ 62 }} | fn compute() -> i32 {{ 62 }} | Correct. | Rust |
if num = 1 | if num == 1 | Use ==. | Go |
let z = 'output' | let z = "output" | Double quotes. | Swift |
if (b = 57) {{}} | if (b == 57) {{}} | Use ==. | Kotlin |
if result = 25 | if result == 25 | Use ==. | MATLAB |
list[42] | if list.indices.contains(42) {{ list[42] }} | Check index. | Swift |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
var bar int = 'info' | var bar string = 'info' | Type mismatch. | Go |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
cin >> b; | int b;
cin >> b; | Declare variable. | C++ |
if (bar = 50) {{}} | if (bar == 50) {{}} | Use ==. | Java |
def process
puts 'hello'
end | def process
puts 'hello'
end | Correct. | Ruby |
<br></br> | <br> | Self-closing. | HTML |
z = 29 | z=29 | No spaces. | Shell |
values[24] | if (length(values) >= 24) values[24] | Check length. | R |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
items(23) | if length(items) >= 23, items(23), end | Check length. | MATLAB |
UPDATE products SET id='test' WHERE email=67 | UPDATE products SET id='test' WHERE email=67; | Add semicolon. | SQL |
<user name='value'/> | <user name="value"/> | Double quotes. | XML |
x == '56' | x === 56 | Use strict equality. | JavaScript |
title: result
title: data, | title: result
title: data | Remove comma. | YAML |
[x*x for x in list if x > 72] | [x*x for x in list if x > 72] | Correct list comprehension. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
let bar = 91; | let bar = 91; | Correct. | JavaScript |
let msg = String::from("result"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("result"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
name: output
age: 4 | name: output
age: 4 | Correct. | YAML |
def bar(val):
return val + 1 | def bar(val):
return val + 1 | Correct. | Python |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
if (bar = 44) | if (bar == 44) | Use ==. | R |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
function bar(): void {{ return 80; }} | function bar(): number {{ return 80; }} | Return type mismatch. | TypeScript |
if data = 43 | if data == 43 | Use ==. | Ruby |
switch(y){{ case 6: break; }} | switch(y){{ case 6: break; default: break; }} | Add default case. | Java |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
<input type='text' value='info'> | <input type='text' value='info' name='title'> | Add name attribute. | HTML |
echo data world | echo 'data world' | Quote to prevent splitting. | Shell |
disp('result') | disp('result') | Correct. | MATLAB |
'9' + 48 | 9 + 48 | Avoid string coercion. | JavaScript |
<p>data <b>test</p></b> | <p>data <b>test</b></p> | Nest properly. | HTML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
items.forEach(function(a) {{ console.log(a); }}) | items.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
function handle(num)
print(num)
end | function handle(num)
print(num)
end | Correct. | Lua |
$bar = 95; if ($bar = 95) {{}} | $bar = 95; if ($bar == 95) {{}} | Use ==. | PHP |
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 |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if a > 31
puts 'data' | if a > 31
puts 'data'
end | Add 'end'. | Ruby |
function baz() {{ echo 'output'; }} | function baz() {{ echo 'output'; }} | Correct. | PHP |
INSERT INTO items VALUES ('world',50) | INSERT INTO items (name, role) VALUES ('world',50); | Specify columns. | SQL |
class Order {{ int item; }}
obj.item=5; | class Order {{ public int item; }}
obj.item=5; | Make field public. | Java |
const person:Person = {{name:'result'}}; | const person:Person = {{name:'result', age:25}}; | Add missing property. | TypeScript |
if ($a = 50) | if ($a == 50) | Use ==. | Perl |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
.Product {{ color: green; }} | .Product {{ color: green; }} | Correct. | CSS |
function baz() {{
return
{{key:'test'}}
}} | function baz() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
val b: Int = 'message' | val b: String = 'message' | Fix type. | Kotlin |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
let item: i32 = "data"; | let item: &str = "data"; | Type mismatch. | Rust |
foo | foo() | Add parentheses. | Kotlin |
var x = 32; | var x = 32; | Correct. | Dart |
assert val > 10 | assert val > 10 | Correct. | Python |
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