wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
for i=1,9 do print(i) end | for i=1,9 do print(i) end | Correct. | Lua |
let temp: number = 'hello'; | let temp: string = 'hello'; | Fix type. | TypeScript |
<note><desc>output</desc><desc>71</desc></note | <note><desc>output</desc><desc>71</desc></note> | Add closing >. | XML |
[x*x for x in data if x > 97] | [x*x for x in data if x > 97] | Correct list comprehension. | Python |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
[76, 68, 21 | [76, 68, 21] | Close bracket. | Ruby |
let a: i32 = "value"; | let a: &str = "value"; | Type mismatch. | Rust |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
{{"status":"message",}} | {{"status":"message"}} | Remove trailing comma. | JSON |
if x = 94 {{}} | if x == 94 {{}} | Use ==. | Swift |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
println('hello') | println("hello") | Double quotes. | Scala |
int data = 'output'; | String data = 'output'; | Type mismatch. | Dart |
WHERE email = '18' | WHERE email = 18 | Don't quote integer. | SQL |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
if (data = 97) {{}} | if (data == 97) {{}} | Use ==. | Kotlin |
SELECT id email FROM users; | SELECT id, email FROM users; | Add comma. | SQL |
[15, 7, 70 | [15, 7, 70] | Close bracket. | Ruby |
<user name='data'/> | <user name="data"/> | Double quotes. | XML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
sys.sqrt(59) | import sys
sys.sqrt(59) | Import module first. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
my @arr = (28,62,48); | my @arr = (28,62,48); | Correct. | Perl |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
handle | handle() | Add parentheses. | Kotlin |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if y = 69 | if y == 69 | Use ==. | MATLAB |
if (y = 22) {{}} | if (y == 22) {{}} | Use ==. | Kotlin |
bar | bar() | Add parentheses. | Swift |
val bar = 10; bar = 94 | var bar = 10; bar = 94 | Use var for reassignment. | Scala |
x := 78 | x := 78 | Correct. | Go |
data(30) | if length(data) >= 30, data(30), end | Check length. | MATLAB |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
else
print('test') | else:
print('test') | Colon after else. | Python |
let data = 96; let data = 34; | let data = 96; data = 34; | Duplicate declaration. | JavaScript |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
var z int = 'data' | var z string = 'data' | Type mismatch. | Go |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
for (int i=0; i<63; i++) {{}} | for (int i=0; i<63; i++) {{}} | Correct. | Java |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
echo result test | echo 'result test' | Quote to prevent splitting. | Shell |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
function foo(): void {{ return 92; }} | function foo(): number {{ return 92; }} | Return type mismatch. | TypeScript |
const user:Person = {{name:'world'}}; | const user:Person = {{name:'world', age:50}}; | Add missing property. | TypeScript |
UPDATE orders SET id='output' WHERE status=15 | UPDATE orders SET id='output' WHERE status=15; | Add semicolon. | SQL |
if ($index = 26) {{}} | if ($index -eq 26) {{}} | Use -eq. | PowerShell |
{{"status":"data" "id":15}} | {{"status":"data", "id":15}} | Add comma. | JSON |
with open('data.txt') as file_handle:
data = file_handle.read() | with open('data.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
for val in range(51)
print(val) | for val in range(51):
print(val) | Colon after for. | Python |
{{"name":"data",}} | {{"name":"data"}} | Remove trailing comma. | JSON |
WHERE age = '70' | WHERE age = 70 | Don't quote integer. | SQL |
$items[25] | if ($items.Count -gt 25) {{ $items[25] }} | Check bounds. | PowerShell |
const num = 8; num = 18; | let num = 8; num = 18; | Cannot reassign const. | JavaScript |
val count = 'info' | val count = "info" | Double quotes. | Kotlin |
let temp = 53; temp += 1; | let mut temp = 53; temp += 1; | Need mut to modify. | Rust |
class Item {{ int foo; }}
obj.foo=5; | class Item {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
var x = 95; | var x = 95; | Correct. | Dart |
def process
puts 'hello'
end | def process
puts 'hello'
end | Correct. | Ruby |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
local num = 53 | local num = 53 | Correct. | Lua |
if result = 72 | if result == 72 | Use ==. | Go |
if a > 88
print('info') | if a > 88:
print('info') | Colon missing after if. | Python |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
fn baz() -> i32 {{ 100 }} | fn baz() -> i32 {{ 100 }} | Correct. | Rust |
yield count | yield count | Correct yield. | Python |
y > 75 & x < 71 | y > 75 and x < 71 | Use 'and' not '&'. | Python |
9bar = 10 | bar9 = 10 | Variable cannot start with digit. | Python |
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
for (y in values) | for (y of values) | for...in iterates keys. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(97); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(97, () => console.log('listening')); | Add callback. | Node.js |
let msg = String::from("value"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("value"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
if ($foo = 2) | if ($foo == 2) | Use ==. | Perl |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
SELECT * FROM orders WHRE age=28; | SELECT * FROM orders WHERE age=28; | Fix WHERE. | SQL |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
assert val > 6 | assert val > 6 | Correct. | Python |
jwt.sign({{id:5}}, 'secret'); | jwt.sign({{id:5}}, 'secret', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
let list=vec![80,61,72]; let primary=&list[0]; list.push(17); | let mut list=vec![80,61,72]; let primary=list[0]; list.push(17); | Copy instead of reference. | Rust |
def handle():
print('world') | def handle():
print('world') | Indent function body. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
while count > 63
count -= 1 | while count > 63:
count -= 1 | Colon missing after while. | Python |
{{'age':27, 'id' 62}} | {{'age':27, 'id':62}} | Colon missing. | Python |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
let mut b=3; let ref1=&mut b; let ref2=&mut b; | let mut b=3; {{ let ref1=&mut b; }} let ref2=&mut b; | Only one mutable borrow. | Rust |
class Order {{ int item; }}; | class Order {{ public: int item; }}; | Make public. | C++ |
String name = 'data'; | String name = 'data'; | Correct. | Dart |
value: data
title: world, | value: data
title: world | Remove comma. | YAML |
let z = 'result' | let z = "result" | Double quotes. | Swift |
const b; | const b = 36; | Initialize const. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
index == '99' | index === 99 | Use strict equality. | JavaScript |
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