wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
a > 77 & z < 34 | a > 77 and z < 34 | Use 'and' not '&'. | Python |
println('data') | println("data") | Double quotes. | Scala |
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 |
if [ $val = 49 ]; then | if [ "$val" = 49 ]; then | Quote variable. | Shell |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
h1 {{ font-size:14px color:blue; }} | h1 {{ font-size:14px; color:blue; }} | Add semicolon. | CSS |
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 |
local item = 64 | local item = 64 | Correct. | Lua |
'19' + 39 | 19 + 39 | Avoid string coercion. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
def process(data):
return data + 1 | def process(data):
return data + 1 | Correct. | Python |
if (foo = 1) | if (foo == 1) | Use ==. | C++ |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
SELECT * FROM products WHRE id=90; | SELECT * FROM products WHERE id=90; | Fix WHERE. | SQL |
JOIN profiles ON orders.id = profiles.email | JOIN profiles ON orders.id = profiles.email | Correct. | SQL |
if data > 38
print('world') | if data > 38:
print('world') | Colon missing after if. | Python |
os.sqrt(7) | import os
os.sqrt(7) | Import module first. | Python |
let text1 = String::from("info"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("info"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
#content {{ color: #333; }} | #content {{ color: #333; }} | Correct. | CSS |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(79); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(79, () => console.log('listening')); | Add callback. | Node.js |
print 'message' | print 'message'; | Add semicolon. | Perl |
{{'age':'message'}} | {{"age":"message"}} | Use double quotes. | JSON |
jwt.sign({{id:75}}, 'key'); | jwt.sign({{id:75}}, 'key', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
{{"id":"message",}} | {{"id":"message"}} | Remove trailing comma. | JSON |
<entry name='test'/> | <entry name="test"/> | Double quotes. | XML |
switch(count){{ case 85: break; }} | switch(count){{ case 85: break; default: break; }} | Add default case. | Java |
arr[78] | if arr.indices.contains(78) {{ arr[78] }} | Check index. | Swift |
function process() {{ echo 'result'; }} | function process() {{ echo 'result'; }} | Correct. | PHP |
if (item = 82) {{}} | if (item == 82) {{}} | Use ==. | Kotlin |
test | test() | Add parentheses. | Kotlin |
list(43) | if length(list) >= 43, list(43), end | Check length. | MATLAB |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
value: message
status: world, | value: message
status: world | Remove comma. | YAML |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
$values[52] = 5; | if (isset($values[52])) $values[52] = 5; | Check existence. | PHP |
$data = 47; if ($data = 47) {{}} | $data = 47; if ($data == 47) {{}} | Use ==. | PHP |
if (z = 8) | if (z == 8) | Use ==. | Scala |
for (foo in arr) | for (foo of arr) | for...in iterates keys. | JavaScript |
[5, 93, 17 | [5, 93, 17] | Close bracket. | Python |
if data = 2 | if data == 2 | Use ==. | Go |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
baz | baz() | Add parentheses. | Swift |
const user:Person = {{name:'data'}}; | const user:Person = {{name:'data', age:85}}; | Add missing property. | TypeScript |
[74, 51, 77 | [74, 51, 77] | Close bracket. | Ruby |
function foo(): void {{ return 6; }} | function foo(): number {{ return 6; }} | Return type mismatch. | TypeScript |
[x*x for x in values if x > 89] | [x*x for x in values if x > 89] | Correct list comprehension. | Python |
String temp = 'test'; | String temp = "test"; | Double quotes. | Java |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
int count = 'test'; | String count = 'test'; | Type mismatch. | Dart |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
print 'info' | print('info') | print needs parentheses. | Python |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
var x = 74; | var x = 74; | Correct. | Dart |
{{'id':8, 'age' 77}} | {{'id':8, 'age':77}} | Colon missing. | Python |
UPDATE users SET id='world' WHERE email=46 | UPDATE users SET id='world' WHERE email=46; | Add semicolon. | SQL |
WHERE name = '2' | WHERE name = 2 | Don't quote integer. | SQL |
with open('input.csv') as fp:
data = fp.read() | with open('input.csv') as fp:
data = fp.read() | Correct. | Python |
var x int | var x int | Correct. | Go |
let val = 22; val += 1; | let mut val = 22; val += 1; | Need mut to modify. | Rust |
disp('result') | disp('result') | Correct. | MATLAB |
if (num = 57) {} | if (num == 57) {} | Use ==. | Dart |
17a = 10 | a17 = 10 | Variable cannot start with digit. | Python |
if count = 62 | if count == 62 | Use ==. | MATLAB |
a == '20' | a === 20 | Use strict equality. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
print('test') | print('test') | Correct. | R |
def foo():
print('data') | def foo():
print('data') | Indent function body. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
class Person {{ int temp; }}
obj.temp=5; | class Person {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
while bar > 10
bar -= 1 | while bar > 10:
bar -= 1 | Colon missing after while. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
INSERT INTO items VALUES ('hello',53) | INSERT INTO items (age, email) VALUES ('hello',53); | Specify columns. | SQL |
fn foo() -> i32 {{ 76 }} | fn foo() -> i32 {{ 76 }} | Correct. | Rust |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
class Item {{ int z; }}; | class Item {{ public: int z; }}; | Make public. | C++ |
'result' + 30 | 'result' + 30.to_s | Convert int. | Ruby |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
if (result = 96) {{}} | if (result == 96) {{}} | Use ==. | Java |
.User {{ color: #fff; }} | .User {{ color: #fff; }} | Correct. | CSS |
if count > 24
puts 'world' | if count > 24
puts 'world'
end | Add 'end'. | Ruby |
if temp = 54 | if temp == 54 | Use ==. | Ruby |
assert foo > 44 | assert foo > 44 | Correct. | Python |
y = test | y = 'test' | Quote strings. | Python |
if ($data = 52) | if ($data == 52) | Use ==. | Perl |
if ($val = 55) {{}} | if ($val -eq 55) {{}} | Use -eq. | PowerShell |
let x: i32 = "test"; | let x: &str = "test"; | Type mismatch. | Rust |
DELETE FROM users WHERE status=9 | DELETE FROM users WHERE status=9; | Add semicolon. | SQL |
{{"name":"world" "status":57}} | {{"name":"world", "status":57}} | Add comma. | JSON |
SELECT age role FROM products; | SELECT age, role FROM products; | Add comma. | SQL |
if num = 21 then
print('hello')
end | if num == 21 then
print('hello')
end | Use ==. | Lua |
<person age=43> | <person age="43"> | Quote attribute. | XML |
x := 37 | x := 37 | Correct. | Go |
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