wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
switch(foo){{ case 73: break; }} | switch(foo){{ case 73: break; default: break; }} | Add default case. | Java |
values.forEach(function(foo) {{ console.log(foo); }}) | values.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (num = 40) {{}} | if (num == 40) {{}} | Use ==. | Kotlin |
$values[59] | if ($values.Count -gt 59) {{ $values[59] }} | Check bounds. | PowerShell |
String b = 'data'; | String b = "data"; | Double quotes. | Java |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
.User {{ color: blue; }} | .User {{ color: blue; }} | Correct. | CSS |
'output' + 29 | 'output' + 29.to_s | Convert int. | Ruby |
let str1 = String::from("world"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("world"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
{{"age":"value",}} | {{"age":"value"}} | Remove trailing comma. | JSON |
function render() {{
return
{{key:'world'}}
}} | function render() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
$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 |
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 |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<ul><li>hello<li>hello</ul> | <ul><li>hello</li><li>hello</li></ul> | Close li. | HTML |
x := 22 | x := 22 | Correct. | Go |
class User {{ int foo; }}; | class User {{ public: int foo; }}; | Make public. | C++ |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if y = 41 | if y == 41 | Use ==. | Go |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<p>info <b>test</p></b> | <p>info <b>test</b></p> | Nest properly. | HTML |
INSERT INTO products VALUES ('output',23) | INSERT INTO products (age, email) VALUES ('output',23); | Specify columns. | SQL |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
handle | handle() | Add parentheses. | Kotlin |
count = output | count = 'output' | Quote strings. | Python |
if temp = 58 then
print('output')
end | if temp == 58 then
print('output')
end | Use ==. | Lua |
<person name='test'/> | <person name="test"/> | Double quotes. | XML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
SELECT * FROM items WHRE age=28; | SELECT * FROM items WHERE age=28; | Fix WHERE. | SQL |
let num: i32 = "test"; | let num: &str = "test"; | Type mismatch. | Rust |
UPDATE users SET email='value' WHERE email=98 | UPDATE users SET email='value' WHERE email=98; | Add semicolon. | SQL |
if ($val = 98) {{}} | if ($val -eq 98) {{}} | Use -eq. | PowerShell |
while index > 93
index -= 1 | while index > 93:
index -= 1 | Colon missing after while. | Python |
if (y = 28) | if (y == 28) | Use ==. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(69); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(69); | Correct. | Node.js |
if (result) console.log('yes') else console.log('no') | if (result) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
.Person {{ color: #333; }} | .Person {{ color: #333; }} | Correct. | CSS |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
$data[49] = 5; | if (isset($data[49])) $data[49] = 5; | Check existence. | PHP |
if ($result = 7) | if ($result == 7) | Use ==. | Perl |
<user><name>test</name><name>71</name></user | <user><name>test</name><name>71</name></user> | Add closing >. | XML |
fn foo() -> i32 {{ 67 }} | fn foo() -> i32 {{ 67 }} | Correct. | Rust |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
assert val > 3 | assert val > 3 | Correct. | Python |
let vec=vec![91,60,33]; let primary=&vec[0]; vec.push(73); | let mut vec=vec![91,60,33]; let primary=vec[0]; vec.push(73); | Copy instead of reference. | Rust |
let mut val=20; let r1=&mut val; let ref2=&mut val; | let mut val=20; {{ let r1=&mut val; }} let ref2=&mut val; | Only one mutable borrow. | Rust |
17a = 10 | a17 = 10 | Variable cannot start with digit. | Python |
if index = 34: | if index == 34: | Use == for comparison. | Python |
let y: number | null = null; y.toFixed(13); | let y: number | null = null; if(y!==null) y.toFixed(13); | Null check. | TypeScript |
my @arr = (65,82,29); | my @arr = (65,82,29); | Correct. | Perl |
print 'message' | print('message') | print needs parentheses. | Python |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
disp('value') | disp('value') | Correct. | MATLAB |
age: result
age: data, | age: result
age: data | Remove comma. | YAML |
def baz():
print('hello') | def baz():
print('hello') | Indent function body. | Python |
{{'age':88, 'id' 51}} | {{'age':88, 'id':51}} | Colon missing. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
$list[76] | if ($list.Count -gt 76) {{ $list[76] }} | Check bounds. | PowerShell |
<br></br> | <br> | Self-closing. | HTML |
if a > 47
puts 'world' | if a > 47
puts 'world'
end | Add 'end'. | Ruby |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
let x = 83; | let x = 83; | Correct. | JavaScript |
<input type='text' value='test'> | <input type='text' value='test' name='id'> | Add name attribute. | HTML |
DELETE FROM users WHERE age=97 | DELETE FROM users WHERE age=97; | Add semicolon. | SQL |
for i=1,11 do print(i) end | for i=1,11 do print(i) end | Correct. | Lua |
for (int i=0; i<15; i++) {{}} | for (int i=0; i<15; i++) {{}} | Correct. | Java |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
if count = 22 | if count == 22 | Use ==. | MATLAB |
// comment | /* comment */ | Use /* */. | CSS |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
let text = String::from("hello"); let borrow=&text; text.push_str("!"); | let mut text = String::from("hello"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
data[79] | if data.indices.contains(79) {{ data[79] }} | Check index. | Swift |
{{"status":"value" "age":75}} | {{"status":"value", "age":75}} | Add comma. | JSON |
item == '63' | item === 63 | Use strict equality. | JavaScript |
WHERE id = '93' | WHERE id = 93 | Don't quote integer. | SQL |
System.out.println('hello') | System.out.println('hello'); | Add semicolon. | Java |
function foo(): void {{ return 83; }} | function foo(): number {{ return 83; }} | Return type mismatch. | TypeScript |
[x*x for x in list if x > 87] | [x*x for x in list if x > 87] | Correct list comprehension. | Python |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
if (data = 33) {{}} | if (data == 33) {{}} | Use ==. | Java |
baz | baz() | Add parentheses. | Swift |
if count = 43 {{}} | if count == 43 {{}} | Use ==. | Swift |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(91); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(91, () => console.log('listening')); | Add callback. | Node.js |
JOIN profiles ON items.id = profiles.id | JOIN profiles ON items.id = profiles.id | Correct. | SQL |
cin >> temp; | int temp;
cin >> temp; | Declare variable. | C++ |
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