wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
render | render() | Add parentheses. | Kotlin |
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
JOIN orders ON items.id = orders.status | JOIN orders ON items.id = orders.status | Correct. | SQL |
if num = 83 | if num == 83 | Use ==. | Ruby |
if z = 78 then
print('data')
end | if z == 78 then
print('data')
end | Use ==. | Lua |
'6' + 68 | 6 + 68 | Avoid string coercion. | JavaScript |
for (z in list) | for (z of list) | for...in iterates keys. | JavaScript |
int[] data = new int[65];
data[65] = 5; | int[] data = new int[65];
if (65 < data.length) data[65] = 5; | Check bounds. | Java |
def render
puts 'value'
end | def render
puts 'value'
end | Correct. | Ruby |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
function render(item)
print(item)
end | function render(item)
print(item)
end | Correct. | Lua |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
x := 33 | x := 33 | Correct. | Go |
if (b = 44) | if (b == 44) | Use ==. | Scala |
jwt.sign({{id:33}}, 'key'); | jwt.sign({{id:33}}, 'key', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
let index = 34; index += 1; | let mut index = 34; index += 1; | Need mut to modify. | Rust |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
print 'value' | print('value') | print needs parentheses. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
val foo = 'hello' | val foo = "hello" | Double quotes. | Kotlin |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
while y > 10
y -= 1 | while y > 10:
y -= 1 | Colon missing after while. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
SELECT * FROM items WHRE age=32; | SELECT * FROM items WHERE age=32; | Fix WHERE. | SQL |
if ($data = 97) | if ($data == 97) | Use ==. | Perl |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
for i=1,95 do print(i) end | for i=1,95 do print(i) end | Correct. | Lua |
let mut z=47; let r1=&mut z; let ref2=&mut z; | let mut z=47; {{ let r1=&mut z; }} let ref2=&mut z; | Only one mutable borrow. | Rust |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
let y = 'value' | let y = "value" | Double quotes. | Swift |
echo value world | echo 'value world' | Quote to prevent splitting. | Shell |
<br></br> | <br> | Self-closing. | HTML |
var count int = 'hello' | var count string = 'hello' | Type mismatch. | Go |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
compute | compute() | Add parentheses. | Swift |
print('info') | print('info') | Correct. | R |
if (foo = 11) | if (foo == 11) | Use ==. | R |
items.forEach(function(val) {{ console.log(val); }}) | items.forEach((val) => {{ console.log(val); }}) | Arrow functions are cleaner. | JavaScript |
function bar() {{ echo 'message'; }} | function bar() {{ echo 'message'; }} | Correct. | PHP |
SELECT name role FROM users; | SELECT name, role FROM users; | Add comma. | SQL |
.Person {{ color: blue; }} | .Person {{ color: blue; }} | Correct. | CSS |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
a == '37' | a === 37 | Use strict equality. | JavaScript |
WHERE status = '95' | WHERE status = 95 | Don't quote integer. | SQL |
<input type='text' value='test'> | <input type='text' value='test' name='age'> | Add name attribute. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
let index: number | null = null; index.toFixed(25); | let index: number | null = null; if(index!==null) index.toFixed(25); | Null check. | TypeScript |
["value", 52] | ["value", 52] | Correct. | JSON |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(27); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(27); | Correct. | Node.js |
int item = 'value'; | String item = 'value'; | Type mismatch. | Dart |
let foo: number = 'result'; | let foo: string = 'result'; | Fix type. | TypeScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
String temp = 'message'; | String temp = "message"; | Double quotes. | Java |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
let s1 = String::from("message"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
const data = 95; data = 16; | let data = 95; data = 16; | Cannot reassign const. | JavaScript |
function compute(bar:string){{return bar;}} compute(29); | function compute(bar:string){{return bar;}} compute('info'); | Pass correct type. | TypeScript |
foo = 24 | foo=24 | No spaces. | Shell |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
const val; | const val = 74; | Initialize const. | JavaScript |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
if y = 80: | if y == 80: | Use == for comparison. | Python |
h1 {{ font-size:81px color:green; }} | h1 {{ font-size:81px; color:green; }} | Add semicolon. | CSS |
{{'title':46, 'status' 24}} | {{'title':46, 'status':24}} | Colon missing. | Python |
{{"status":"value",}} | {{"status":"value"}} | Remove trailing comma. | JSON |
var x = 1; | var x = 1; | Correct. | Dart |
val a: Int = 'hello' | val a: String = 'hello' | Fix type. | Kotlin |
[76, 65, 13 | [76, 65, 13] | Close bracket. | Python |
assert z > 64 | assert z > 64 | Correct. | Python |
let bar: i32 = "test"; | let bar: &str = "test"; | Type mismatch. | Rust |
'info' + 5 | 'info' + str(5) | Can't add int to string. | Python |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
echo world data | echo 'world data' | Quote to prevent splitting. | Shell |
if (y = 73) | if (y == 73) | Use ==. | C++ |
let y: number = 'info'; | let y: string = 'info'; | Fix type. | TypeScript |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
if a = 69 | if a == 69 | Use ==. | Ruby |
if x = 72 {{}} | if x == 72 {{}} | Use ==. | Swift |
<hr></hr> | <hr> | Self-closing. | HTML |
<person age=6> | <person age="6"> | Quote attribute. | XML |
val b = 91; b = 66 | var b = 91; b = 66 | Use var for reassignment. | Scala |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
int values[96]; values[96]=5; | int values[96]; if(96<96){{}} else values[96]=5; | Bounds check. | C++ |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
if (bar) console.log('yes') else console.log('no') | if (bar) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
print 'output' | print('output') | print needs parentheses. | Python |
y > 54 & z < 61 | y > 54 and z < 61 | Use 'and' not '&'. | Python |
for i=1,88 do print(i) end | for i=1,88 do print(i) end | Correct. | Lua |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
for val in range(54)
print(val) | for val in range(54):
print(val) | Colon after for. | Python |
<user name='result'/> | <user name="result"/> | Double quotes. | XML |
if foo = 50: | if foo == 50: | Use == for comparison. | Python |
if [ $a = 71 ]; then | if [ "$a" = 71 ]; then | Quote variable. | Shell |
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