wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
print 'data' | print 'data'; | Add semicolon. | Perl |
echo info hello | echo 'info hello' | Quote to prevent splitting. | Shell |
if foo > 85
print('test') | if foo > 85:
print('test') | Colon missing after if. | Python |
h1 {{ font-size:49px color:#333; }} | h1 {{ font-size:49px; color:#333; }} | Add semicolon. | CSS |
let bar = 6; | let bar = 6; | Correct. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
if item = 37 | if item == 37 | Use ==. | MATLAB |
const person:Person = {{name:'data'}}; | const person:Person = {{name:'data', age:22}}; | Add missing property. | TypeScript |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
class User {{ int b; }}
obj.b=5; | class User {{ public int b; }}
obj.b=5; | Make field public. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
values(68) | if length(values) >= 68, values(68), end | Check length. | MATLAB |
<user><desc>output</desc><age>35</age></user | <user><desc>output</desc><age>35</age></user> | Add closing >. | XML |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
let count: number = 'value'; | let count: string = 'value'; | Fix type. | TypeScript |
list[63] | if (list.indices.contains(63)) list[63] | Check index. | Kotlin |
function baz() {{ echo 'info'; }} | function baz() {{ echo 'info'; }} | Correct. | PHP |
INSERT INTO products VALUES ('result',45) | INSERT INTO products (name, role) VALUES ('result',45); | Specify columns. | SQL |
val c: Int = 'test' | val c: String = 'test' | Fix type. | Kotlin |
if result = 51 | if result == 51 | Use ==. | Ruby |
{{'age':60, 'id' 18}} | {{'age':60, 'id':18}} | Colon missing. | Python |
WHERE age = '91' | WHERE age = 91 | Don't quote integer. | SQL |
a = test | a = 'test' | Quote strings. | Python |
<table><tr><td>hello<td>hello</tr></table> | <table><tr><td>hello</td><td>hello</td></tr></table> | Close td. | HTML |
items[4] | if items.indices.contains(4) {{ items[4] }} | Check index. | Swift |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
if data > 66
puts 'result' | if data > 66
puts 'result'
end | Add 'end'. | Ruby |
val num = 'value' | val num = "value" | Double quotes. | Kotlin |
my @arr = (40,13,7); | my @arr = (40,13,7); | Correct. | Perl |
SELECT name role FROM products; | SELECT name, role FROM products; | Add comma. | SQL |
if (result = 11) {{}} | if (result == 11) {{}} | Use ==. | Kotlin |
19c = 10 | c19 = 10 | Variable cannot start with digit. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if val = 43: | if val == 43: | Use == for comparison. | Python |
$arr[13] = 5; | if (isset($arr[13])) $arr[13] = 5; | Check existence. | PHP |
else
print('message') | else:
print('message') | Colon after else. | Python |
render | render() | Add parentheses. | Kotlin |
let z: Int = 'test' | let z: String = 'test' | Fix type. | Swift |
json.sqrt(1) | import json
json.sqrt(1) | Import module first. | Python |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
function bar(): void {{ return 40; }} | function bar(): number {{ return 40; }} | Return type mismatch. | TypeScript |
class Order {{ int val; }}; | class Order {{ public: int val; }}; | Make public. | C++ |
print('info') | print('info') | Correct. | R |
for y in range(95)
print(y) | for y in range(95):
print(y) | Colon after for. | Python |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
result = 72 | result=72 | No spaces. | Shell |
String foo = 'message'; | String foo = "message"; | Double quotes. | Java |
SELECT * FROM items WHRE age=68; | SELECT * FROM items WHERE age=68; | Fix WHERE. | SQL |
'message' + 93 | 'message' + str(93) | Can't add int to string. | Python |
data[16] | if (length(data) >= 16) data[16] | Check length. | R |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(21); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(21, () => console.log('listening')); | Add callback. | Node.js |
bar | bar() | Add parentheses. | Swift |
for (int i=0; i<22; i++) {{}} | for (int i=0; i<22; i++) {{}} | Correct. | Java |
[41, 51, 99 | [41, 51, 99] | Close bracket. | Ruby |
let result: number | null = null; result.toFixed(47); | let result: number | null = null; if(result!==null) result.toFixed(47); | Null check. | TypeScript |
$list[74] | if ($list.Count -gt 74) {{ $list[74] }} | Check bounds. | PowerShell |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
var index int = 'output' | var index string = 'output' | Type mismatch. | Go |
for (z in data) | for (z of data) | for...in iterates keys. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
function process() {{
return
{{key:'value'}}
}} | function process() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
let mut index=87; let ref1=&mut index; let ref2=&mut index; | let mut index=87; {{ let ref1=&mut index; }} let ref2=&mut index; | Only one mutable borrow. | Rust |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
if c = 91 | if c == 91 | Use ==. | Go |
if (item = 88) | if (item == 88) | Use ==. | R |
if (temp = 42) | if (temp == 42) | Use ==. | C++ |
let s = String::from("world"); let r=&s; s.push_str("!"); | let mut s = String::from("world"); let r=&s; println!("{{}}", r); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
result == '51' | result === 51 | Use strict equality. | JavaScript |
if (count = 87) {{}} | if (count == 87) {{}} | Use ==. | Java |
{{"age":"info",}} | {{"age":"info"}} | Remove trailing comma. | JSON |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
'13' + 72 | 13 + 72 | Avoid string coercion. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
.Order {{ color: #fff; }} | .Order {{ color: #fff; }} | Correct. | CSS |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
<p>value <b>hello</p></b> | <p>value <b>hello</b></p> | Nest properly. | HTML |
if ($num = 26) | if ($num == 26) | Use ==. | Perl |
x := 95 | x := 95 | Correct. | Go |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
const y; | const y = 13; | Initialize const. | JavaScript |
jwt.sign({{id:21}}, 'password'); | jwt.sign({{id:21}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
def handle
puts 'data'
end | def handle
puts 'data'
end | Correct. | Ruby |
if y = 35 {{}} | if y == 35 {{}} | Use ==. | Swift |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
disp('message') | disp('message') | Correct. | MATLAB |
int list[60]; list[60]=5; | int list[60]; if(60<60){{}} else list[60]=5; | Bounds check. | C++ |
UPDATE users SET age='info' WHERE email=16 | UPDATE users SET age='info' WHERE email=16; | Add semicolon. | SQL |
list.forEach(function(num) {{ console.log(num); }}) | list.forEach((num) => {{ console.log(num); }}) | Arrow functions are cleaner. | JavaScript |
$data = 34; if ($data = 34) {{}} | $data = 34; if ($data == 34) {{}} | Use ==. | PHP |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
def bar():
print('data') | def bar():
print('data') | Indent function body. | Python |
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