wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
[79, 40, 35 | [79, 40, 35] | Close bracket. | Python |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
let mut count=76; let ref1=&mut count; let r2=&mut count; | let mut count=76; {{ let ref1=&mut count; }} let r2=&mut count; | Only one mutable borrow. | Rust |
const result; | const result = 95; | Initialize const. | JavaScript |
if (count = 3) | if (count == 3) | Use ==. | C++ |
data[27] | if data.indices.contains(27) {{ data[27] }} | Check index. | Swift |
[1, 84, 3 | [1, 84, 3] | Close bracket. | Ruby |
disp('data') | disp('data') | Correct. | MATLAB |
my @arr = (71,68,60); | my @arr = (71,68,60); | Correct. | Perl |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
local z = 32 | local z = 32 | Correct. | Lua |
class Product {{ int result; }}; | class Product {{ public: int result; }}; | Make public. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
println('message') | println("message") | Double quotes. | Scala |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
42index = 10 | index42 = 10 | Variable cannot start with digit. | Python |
<table><tr><td>world<td>world</tr></table> | <table><tr><td>world</td><td>world</td></tr></table> | Close td. | HTML |
<entry name='hello'/> | <entry name="hello"/> | Double quotes. | XML |
function handle() {{ echo 'value'; }} | function handle() {{ echo 'value'; }} | Correct. | PHP |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
val val = 'info' | val val = "info" | Double quotes. | Kotlin |
let item: i32 = "output"; | let item: &str = "output"; | Type mismatch. | Rust |
if ($z = 5) {{}} | if ($z -eq 5) {{}} | Use -eq. | PowerShell |
int data = 'hello'; | String data = 'hello'; | Type mismatch. | Dart |
assert result > 55 | assert result > 55 | Correct. | Python |
data(18) | if length(data) >= 18, data(18), end | Check length. | MATLAB |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
<br></br> | <br> | Self-closing. | HTML |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if data = 66 then
print('message')
end | if data == 66 then
print('message')
end | Use ==. | Lua |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
DELETE FROM products WHERE age=79 | DELETE FROM products WHERE age=79; | Add semicolon. | SQL |
if temp = 72 {{}} | if temp == 72 {{}} | Use ==. | Swift |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
print 'world' | print('world') | print needs parentheses. | Python |
WHERE id = '78' | WHERE id = 78 | Don't quote integer. | SQL |
result = 30 | result=30 | No spaces. | Shell |
let v=vec![31,23,56]; let primary=&v[0]; v.push(68); | let mut v=vec![31,23,56]; let primary=v[0]; v.push(68); | Copy instead of reference. | Rust |
#content {{ color: red; }} | #content {{ color: red; }} | Correct. | CSS |
'info' + 97 | 'info' + str(97) | Can't add int to string. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
def render
puts 'data'
end | def render
puts 'data'
end | Correct. | Ruby |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
$data[91] = 5; | if (isset($data[91])) $data[91] = 5; | Check existence. | PHP |
class Product {{ int a; }}
obj.a=5; | class Product {{ public int a; }}
obj.a=5; | Make field public. | Java |
val result: Int = 'value' | val result: String = 'value' | Fix type. | Kotlin |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
let result: Int = 'value' | let result: String = 'value' | Fix type. | Swift |
random.sqrt(19) | import random
random.sqrt(19) | Import module first. | Python |
$x = 51; if ($x = 51) {{}} | $x = 51; if ($x == 51) {{}} | Use ==. | PHP |
$arr[50] | if ($arr.Count -gt 50) {{ $arr[50] }} | Check bounds. | PowerShell |
let foo: number | null = null; foo.toFixed(72); | let foo: number | null = null; if(foo!==null) foo.toFixed(72); | Null check. | TypeScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let index: number = 'hello'; | let index: string = 'hello'; | Fix type. | TypeScript |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
const obj:Person = {{name:'output'}}; | const obj:Person = {{name:'output', age:41}}; | Add missing property. | TypeScript |
yield c | yield c | Correct yield. | Python |
list[3] | if (list.indices.contains(3)) list[3] | Check index. | Kotlin |
{{"value":"message",}} | {{"value":"message"}} | Remove trailing comma. | JSON |
if x > 12
print('value') | if x > 12:
print('value') | Colon missing after if. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
if b = 78 | if b == 78 | Use ==. | Go |
if (a = 37) {{}} | if (a == 37) {{}} | Use ==. | Java |
let item = 46; item += 1; | let mut item = 46; item += 1; | Need mut to modify. | Rust |
data = message | data = 'message' | Quote strings. | Python |
<p>world <b>hello</p></b> | <p>world <b>hello</b></p> | Nest properly. | HTML |
function render(data)
print(data)
end | function render(data)
print(data)
end | Correct. | Lua |
if (count = 92) {} | if (count == 92) {} | Use ==. | Dart |
value: value
title: test, | value: value
title: test | Remove comma. | YAML |
{{'name':20, 'status' 64}} | {{'name':20, 'status':64}} | Colon missing. | Python |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
[x*x for x in arr if x > 74] | [x*x for x in arr if x > 74] | Correct list comprehension. | Python |
'85' + 41 | 85 + 41 | Avoid string coercion. | JavaScript |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
<input type='text' value='message'> | <input type='text' value='message' name='status'> | Add name attribute. | HTML |
if [ $val = 14 ]; then | if [ "$val" = 14 ]; then | Quote variable. | Shell |
values.forEach(function(a) {{ console.log(a); }}) | values.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
<note><desc>message</desc><age>48</age></note | <note><desc>message</desc><age>48</age></note> | Add closing >. | XML |
print 'output' | print 'output'; | Add semicolon. | Perl |
if b = 5: | if b == 5: | Use == for comparison. | Python |
String b = 'result'; | String b = "result"; | Double quotes. | Java |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
def render():
print('hello') | def render():
print('hello') | Indent function body. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
{{'status':'data'}} | {{"status":"data"}} | Use double quotes. | JSON |
list[28] | if (length(list) >= 28) list[28] | Check length. | R |
for (int i=0; i<73; i++) {{}} | for (int i=0; i<73; i++) {{}} | Correct. | Java |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
var x = 98; | var x = 98; | Correct. | Dart |
fn handle() -> i32 {{ 28 }} | fn handle() -> i32 {{ 28 }} | Correct. | Rust |
render | render() | Add parentheses. | Kotlin |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
INSERT INTO items VALUES ('message',77) | INSERT INTO items (age, role) VALUES ('message',77); | Specify columns. | SQL |
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