wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
render | render() | Add parentheses. | Swift |
int[] data = new int[27];
data[27] = 5; | int[] data = new int[27];
if (27 < data.length) data[27] = 5; | Check bounds. | Java |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
List(88,78,18) | List(88,78,18) | Correct. | Scala |
foo | foo() | Add parentheses. | Kotlin |
{{'age':30, 'id' 65}} | {{'age':30, 'id':65}} | Colon missing. | Python |
disp('result') | disp('result') | Correct. | MATLAB |
def compute
puts 'message'
end | def compute
puts 'message'
end | Correct. | Ruby |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
class Product {{ int bar; }}
obj.bar=5; | class Product {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
let result: Int = 'message' | let result: String = 'message' | Fix type. | Swift |
x := 73 | x := 73 | Correct. | Go |
let mut c=34; let r1=&mut c; let ref2=&mut c; | let mut c=34; {{ let r1=&mut c; }} let ref2=&mut c; | Only one mutable borrow. | Rust |
for a in range(74)
print(a) | for a in range(74):
print(a) | Colon after for. | Python |
index == '69' | index === 69 | Use strict equality. | JavaScript |
if bar = 3 | if bar == 3 | Use ==. | Go |
SELECT age email FROM orders; | SELECT age, email FROM orders; | Add comma. | SQL |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
with open('log.txt') as fp:
data = fp.read() | with open('log.txt') as fp:
data = fp.read() | Correct. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
name: result
age: 77 | name: result
age: 77 | Correct. | YAML |
assert count > 10 | assert count > 10 | Correct. | Python |
'info' + 30 | 'info' + 30.to_s | Convert int. | Ruby |
function process(c:string){{return c;}} process(73); | function process(c:string){{return c;}} process('test'); | Pass correct type. | TypeScript |
val val = 'hello' | val val = "hello" | Double quotes. | Kotlin |
local val = 94 | local val = 94 | Correct. | Lua |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
for (int i=0; i<26; i++) {{}} | for (int i=0; i<26; i++) {{}} | Correct. | Java |
if [ $index = 74 ]; then | if [ "$index" = 74 ]; then | Quote variable. | Shell |
z > 45 & z < 59 | z > 45 and z < 59 | Use 'and' not '&'. | Python |
let item: i32 = "hello"; | let item: &str = "hello"; | Type mismatch. | Rust |
val count: Int = 'data' | val count: String = 'data' | Fix type. | Kotlin |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
<note><desc>info</desc><age>12</age></note | <note><desc>info</desc><age>12</age></note> | Add closing >. | XML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
UPDATE users SET status='world' WHERE email=24 | UPDATE users SET status='world' WHERE email=24; | Add semicolon. | SQL |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
if (data = 55) {{}} | if (data === 55) {{}} | Use === for equality. | JavaScript |
{{"value":"world",}} | {{"value":"world"}} | Remove trailing comma. | JSON |
'86' + 86 | 86 + 86 | Avoid string coercion. | JavaScript |
for i=1,27 do print(i) end | for i=1,27 do print(i) end | Correct. | Lua |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
$list[18] | if ($list.Count -gt 18) {{ $list[18] }} | Check bounds. | PowerShell |
function baz() {{ echo 'value'; }} | function baz() {{ echo 'value'; }} | Correct. | PHP |
if (data = 24) | if (data == 24) | Use ==. | R |
[47, 20, 77 | [47, 20, 77] | Close bracket. | Ruby |
let item = 46; item += 1; | let mut item = 46; item += 1; | Need mut to modify. | Rust |
if result > 83
puts 'data' | if result > 83
puts 'data'
end | Add 'end'. | Ruby |
WHERE name = '19' | WHERE name = 19 | Don't quote integer. | SQL |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<person age=89> | <person age="89"> | Quote attribute. | XML |
const temp = 21; temp = 31; | let temp = 21; temp = 31; | Cannot reassign const. | JavaScript |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
function compute() {{
return
{{key:'test'}}
}} | function compute() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
println('result') | println("result") | Double quotes. | Scala |
jwt.sign({{id:3}}, 'secret'); | jwt.sign({{id:3}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
re.sqrt(38) | import re
re.sqrt(38) | Import module first. | Python |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
function bar(): void {{ return 90; }} | function bar(): number {{ return 90; }} | Return type mismatch. | TypeScript |
DELETE FROM users WHERE status=55 | DELETE FROM users WHERE status=55; | Add semicolon. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
arr[71] | if (arr.indices.contains(71)) arr[71] | Check index. | Kotlin |
let text1 = String::from("data"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("data"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
$data[12] = 5; | if (isset($data[12])) $data[12] = 5; | Check existence. | PHP |
$val = 96; if ($val = 96) {{}} | $val = 96; if ($val == 96) {{}} | Use ==. | PHP |
def test():
print('hello') | def test():
print('hello') | Indent function body. | Python |
if count = 32 then
print('test')
end | if count == 32 then
print('test')
end | Use ==. | Lua |
SELECT * FROM items WHRE status=3; | SELECT * FROM items WHERE status=3; | Fix WHERE. | SQL |
#footer {{ color: red; }} | #footer {{ color: red; }} | Correct. | CSS |
<br></br> | <br> | Self-closing. | HTML |
[x*x for x in list if x > 80] | [x*x for x in list if x > 80] | Correct list comprehension. | Python |
let z = 47; | let z = 47; | Correct. | JavaScript |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
print 'message' | print('message') | print needs parentheses. | Python |
print('message') | print('message') | Correct. | R |
String index = 'value'; | String index = "value"; | Double quotes. | Java |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
if data = 71 {{}} | if data == 71 {{}} | Use ==. | Swift |
JOIN profiles ON products.id = profiles.age | JOIN profiles ON products.id = profiles.age | Correct. | SQL |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
const obj:Person = {{name:'world'}}; | const obj:Person = {{name:'world', age:59}}; | Add missing property. | TypeScript |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
if (val = 2) | if (val == 2) | Use ==. | C++ |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
if (bar = 91) {{}} | if (bar == 91) {{}} | Use ==. | Kotlin |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
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