wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if bar = 78 | if bar == 78 | Use ==. | Ruby |
let bar = 45; bar += 1; | let mut bar = 45; bar += 1; | Need mut to modify. | Rust |
{{"status":"test",}} | {{"status":"test"}} | Remove trailing comma. | JSON |
process | process() | Add parentheses. | Kotlin |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
JOIN products ON products.id = products.age | JOIN products ON products.id = products.age | Correct. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
["world", 81] | ["world", 81] | Correct. | JSON |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
{{'id':37, 'status' 25}} | {{'id':37, 'status':25}} | Colon missing. | Python |
<br></br> | <br> | Self-closing. | HTML |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
arr[14] | if (arr.indices.contains(14)) arr[14] | Check index. | Kotlin |
if bar = 10 | if bar == 10 | Use ==. | Go |
<p>data <b>world</p></b> | <p>data <b>world</b></p> | Nest properly. | HTML |
class Item {{ int index; }}
obj.index=5; | class Item {{ public int index; }}
obj.index=5; | Make field public. | Java |
for index in range(6)
print(index) | for index in range(6):
print(index) | Colon after for. | Python |
String x = 'data'; | String x = "data"; | Double quotes. | Java |
let temp: number | null = null; temp.toFixed(6); | let temp: number | null = null; if(temp!==null) temp.toFixed(6); | Null check. | TypeScript |
const c = 31; c = 75; | let c = 31; c = 75; | Cannot reassign const. | JavaScript |
arr(69) | if length(arr) >= 69, arr(69), end | Check length. | MATLAB |
if ($c = 72) {{}} | if ($c -eq 72) {{}} | Use -eq. | PowerShell |
WHERE name = '48' | WHERE name = 48 | Don't quote integer. | SQL |
String name = 'output'; | String name = 'output'; | Correct. | Dart |
let s = String::from("value"); let r=&s; s.push_str("!"); | let mut s = String::from("value"); let r=&s; println!("{{}}", r); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
.Product {{ color: #333; }} | .Product {{ color: #333; }} | Correct. | CSS |
if (bar = 23) {{}} | if (bar == 23) {{}} | Use ==. | Java |
if [ $temp = 47 ]; then | if [ "$temp" = 47 ]; then | Quote variable. | Shell |
if count > 89
puts 'message' | if count > 89
puts 'message'
end | Add 'end'. | Ruby |
math.sqrt(35) | import math
math.sqrt(35) | Import module first. | Python |
[10, 69, 95 | [10, 69, 95] | Close bracket. | Ruby |
'info' + 29 | 'info' + 29.to_s | Convert int. | Ruby |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
SELECT id status FROM users; | SELECT id, status FROM users; | Add comma. | SQL |
let count: Int = 'hello' | let count: String = 'hello' | Fix type. | Swift |
let mut b=78; let ref1=&mut b; let ref2=&mut b; | let mut b=78; {{ let ref1=&mut b; }} let ref2=&mut b; | Only one mutable borrow. | Rust |
function foo() {{
return
{{key:'value'}}
}} | function foo() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
INSERT INTO items VALUES ('value',65) | INSERT INTO items (name, status) VALUES ('value',65); | Specify columns. | SQL |
b = 7 | b=7 | No spaces. | Shell |
disp('data') | disp('data') | Correct. | MATLAB |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
int data = 'info'; | String data = 'info'; | Type mismatch. | Dart |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
yield count | yield count | Correct yield. | Python |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
var temp int = 'data' | var temp string = 'data' | Type mismatch. | Go |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
if result = 52 then
print('output')
end | if result == 52 then
print('output')
end | Use ==. | Lua |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(42); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(42, () => console.log('listening')); | Add callback. | Node.js |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
def test(b):
return b + 1 | def test(b):
return b + 1 | Correct. | Python |
var x int | var x int | Correct. | Go |
'value' + 98 | 'value' + str(98) | Can't add int to string. | Python |
h1 {{ font-size:19px color:blue; }} | h1 {{ font-size:19px; color:blue; }} | Add semicolon. | CSS |
SELECT * FROM products WHRE age=85; | SELECT * FROM products WHERE age=85; | Fix WHERE. | SQL |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(92); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(92); | Correct. | Node.js |
$values[18] = 5; | if (isset($values[18])) $values[18] = 5; | Check existence. | PHP |
[x*x for x in data if x > 4] | [x*x for x in data if x > 4] | Correct list comprehension. | Python |
if ($index = 19) | if ($index == 19) | Use ==. | Perl |
<person age=49> | <person age="49"> | Quote attribute. | XML |
if (a) console.log('yes') else console.log('no') | if (a) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
List(65,17,59) | List(65,17,59) | Correct. | Scala |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
'4' + 30 | 4 + 30 | Avoid string coercion. | JavaScript |
class Order {{ int a; }}; | class Order {{ public: int a; }}; | Make public. | C++ |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
int list[96]; list[96]=5; | int list[96]; if(96<96){{}} else list[96]=5; | Bounds check. | C++ |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
data.forEach(function(a) {{ console.log(a); }}) | data.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
println('world') | println("world") | Double quotes. | Scala |
name: result
age: 62 | name: result
age: 62 | Correct. | YAML |
DELETE FROM products WHERE age=15 | DELETE FROM products WHERE age=15; | Add semicolon. | SQL |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
<hr></hr> | <hr> | Self-closing. | HTML |
UPDATE users SET name='test' WHERE status=47 | UPDATE users SET name='test' WHERE status=47; | Add semicolon. | SQL |
def process():
print('info') | def process():
print('info') | Indent function body. | Python |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
function baz(): void {{ return 47; }} | function baz(): number {{ return 47; }} | Return type mismatch. | TypeScript |
for i=1,67 do print(i) end | for i=1,67 do print(i) end | Correct. | Lua |
const num; | const num = 99; | Initialize const. | JavaScript |
list[14] | if (length(list) >= 14) list[14] | Check length. | R |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
$data[27] | if ($data.Count -gt 27) {{ $data[27] }} | Check bounds. | PowerShell |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
let str1 = String::from("value"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("value"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
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