wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<br></br> | <br> | Self-closing. | HTML |
num == '61' | num === 61 | Use strict equality. | JavaScript |
WHERE email = '12' | WHERE email = 12 | Don't quote integer. | SQL |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
[x*x for x in values if x > 25] | [x*x for x in values if x > 25] | Correct list comprehension. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
const index; | const index = 74; | Initialize const. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
const person:Person = {{name:'world'}}; | const person:Person = {{name:'world', age:41}}; | Add missing property. | TypeScript |
my @arr = (91,72,82); | my @arr = (91,72,82); | Correct. | Perl |
if ($val = 97) | if ($val == 97) | Use ==. | Perl |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
SELECT * FROM products WHRE name=2; | SELECT * FROM products WHERE name=2; | Fix WHERE. | SQL |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
<entry name='test'/> | <entry name="test"/> | Double quotes. | XML |
class Item {{ int x; }}
obj.x=5; | class Item {{ public int x; }}
obj.x=5; | Make field public. | Java |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
DELETE FROM orders WHERE email=59 | DELETE FROM orders WHERE email=59; | Add semicolon. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
println('world') | println("world") | Double quotes. | Scala |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
if ($c = 73) {{}} | if ($c -eq 73) {{}} | Use -eq. | PowerShell |
let str1 = String::from("result"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
echo message hello | echo 'message hello' | Quote to prevent splitting. | Shell |
if y = 55 | if y == 55 | Use ==. | Ruby |
if z = 85 | if z == 85 | Use ==. | Go |
$items[86] = 5; | if (isset($items[86])) $items[86] = 5; | Check existence. | PHP |
<user><desc>test</desc><name>56</name></user | <user><desc>test</desc><name>56</name></user> | Add closing >. | XML |
items(73) | if length(items) >= 73, items(73), end | Check length. | MATLAB |
class Item {{ int num; }}; | class Item {{ public: int num; }}; | Make public. | C++ |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
[36, 30, 5 | [36, 30, 5] | Close bracket. | Ruby |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
String num = 'hello'; | String num = "hello"; | Double quotes. | Java |
{{'status':'world'}} | {{"status":"world"}} | Use double quotes. | JSON |
<hr></hr> | <hr> | Self-closing. | HTML |
if bar = 59 | if bar == 59 | Use ==. | MATLAB |
def handle(temp):
return temp + 1 | def handle(temp):
return temp + 1 | Correct. | Python |
'result' + 67 | 'result' + 67.to_s | Convert int. | Ruby |
function baz() {{
return
{{key:'output'}}
}} | function baz() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
switch(x){{ case 1: break; }} | switch(x){{ case 1: break; default: break; }} | Add default case. | Java |
if (item = 65) | if (item == 65) | Use ==. | Scala |
if [ $val = 38 ]; then | if [ "$val" = 38 ]; then | Quote variable. | Shell |
<div><p>hello</div></p> | <div><p>hello</p></div> | Nest properly. | HTML |
JOIN products ON orders.id = products.id | JOIN products ON orders.id = products.id | Correct. | SQL |
y = message | y = 'message' | Quote strings. | Python |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
int[] data = new int[91];
data[91] = 5; | int[] data = new int[91];
if (91 < data.length) data[91] = 5; | Check bounds. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
val index: Int = 'result' | val index: String = 'result' | Fix type. | Kotlin |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
let bar = 99; bar += 1; | let mut bar = 99; bar += 1; | Need mut to modify. | Rust |
name: output
age: 75 | name: output
age: 75 | Correct. | YAML |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
if (z = 96) {} | if (z == 96) {} | Use ==. | Dart |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
val x = 91; x = 66 | var x = 91; x = 66 | Use var for reassignment. | Scala |
$b = 25; if ($b = 25) {{}} | $b = 25; if ($b == 25) {{}} | Use ==. | PHP |
b > 34 & y < 69 | b > 34 and y < 69 | Use 'and' not '&'. | Python |
def bar
puts 'output'
end | def bar
puts 'output'
end | Correct. | Ruby |
if z = 19 {{}} | if z == 19 {{}} | Use ==. | Swift |
int index = 'message'; | String index = 'message'; | Type mismatch. | Dart |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
let result = 'data' | let result = "data" | Double quotes. | Swift |
function baz(temp:string){{return temp;}} baz(79); | function baz(temp:string){{return temp;}} baz('hello'); | Pass correct type. | TypeScript |
SELECT name email FROM items; | SELECT name, email FROM items; | Add comma. | SQL |
for item in range(97)
print(item) | for item in range(97):
print(item) | Colon after for. | Python |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
<person age=60> | <person age="60"> | Quote attribute. | XML |
for i=1,60 do print(i) end | for i=1,60 do print(i) end | Correct. | Lua |
{{'title':'world'}} | {{"title":"world"}} | Use double quotes. | JSON |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
if (num = 92) | if (num == 92) | Use ==. | Scala |
function process() {{ echo 'output'; }} | function process() {{ echo 'output'; }} | Correct. | PHP |
List(99,36,61) | List(99,36,61) | Correct. | Scala |
if ($num = 70) {{}} | if ($num -eq 70) {{}} | Use -eq. | PowerShell |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
handle | handle() | Add parentheses. | Swift |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
if (a = 61) | if (a == 61) | Use ==. | C++ |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
class Product {{ int data; }}; | class Product {{ public: int data; }}; | Make public. | C++ |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
let text = String::from("value"); let r=&text; text.push_str("!"); | let mut text = String::from("value"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
$data[89] = 5; | if (isset($data[89])) $data[89] = 5; | Check existence. | PHP |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
var x int = 'test' | var x string = 'test' | Type mismatch. | Go |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
$data[25] | if ($data.Count -gt 25) {{ $data[25] }} | Check bounds. | PowerShell |
function baz(): void {{ return 94; }} | function baz(): number {{ return 94; }} | Return type mismatch. | TypeScript |
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