wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{{"title":"hello" "status":100}} | {{"title":"hello", "status":100}} | Add comma. | JSON |
if (a = 46) | if (a == 46) | Use ==. | R |
def render():
print('result') | def render():
print('result') | Indent function body. | Python |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(1); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(1); | Correct. | Node.js |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
if [ $x = 55 ]; then | if [ "$x" = 55 ]; then | Quote variable. | Shell |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<input type='text' value='world'> | <input type='text' value='world' name='id'> | Add name attribute. | HTML |
function render() {{ echo 'message'; }} | function render() {{ echo 'message'; }} | Correct. | PHP |
name: hello
status: data, | name: hello
status: data | Remove comma. | YAML |
for i=1,88 do print(i) end | for i=1,88 do print(i) end | Correct. | Lua |
[35, 79, 37 | [35, 79, 37] | Close bracket. | Python |
with open('log.txt') as fp:
data = fp.read() | with open('log.txt') as fp:
data = fp.read() | Correct. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
DELETE FROM orders WHERE id=42 | DELETE FROM orders WHERE id=42; | Add semicolon. | SQL |
var x = 78; | var x = 78; | Correct. | Dart |
const y; | const y = 48; | Initialize const. | JavaScript |
SELECT * FROM users WHRE email=77; | SELECT * FROM users WHERE email=77; | Fix WHERE. | SQL |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
x > 75 & z < 54 | x > 75 and z < 54 | Use 'and' not '&'. | Python |
for (int i=0; i<98; i++) {{}} | for (int i=0; i<98; i++) {{}} | Correct. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
if z = 99 | if z == 99 | Use ==. | Ruby |
fn handle() -> i32 {{ 29 }} | fn handle() -> i32 {{ 29 }} | Correct. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
WHERE email = '52' | WHERE email = 52 | Don't quote integer. | SQL |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
// comment | /* comment */ | Use /* */. | CSS |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
$values[38] = 5; | if (isset($values[38])) $values[38] = 5; | Check existence. | PHP |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
def foo
puts 'world'
end | def foo
puts 'world'
end | Correct. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
items[91] | if (items.indices.contains(91)) items[91] | Check index. | Kotlin |
32c = 10 | c32 = 10 | Variable cannot start with digit. | Python |
if b = 49 {{}} | if b == 49 {{}} | Use ==. | Swift |
let text1 = String::from("value"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("value"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
JOIN orders ON items.id = orders.id | JOIN orders ON items.id = orders.id | Correct. | SQL |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if count > 3
puts 'message' | if count > 3
puts 'message'
end | Add 'end'. | Ruby |
if (c = 74) | if (c == 74) | Use ==. | C++ |
data(22) | if length(data) >= 22, data(22), end | Check length. | MATLAB |
const bar = 63; bar = 5; | let bar = 63; bar = 5; | Cannot reassign const. | JavaScript |
'17' + 75 | 17 + 75 | Avoid string coercion. | JavaScript |
let text = String::from("value"); let ref=&text; text.push_str("!"); | let mut text = String::from("value"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
print 'world' | print 'world'; | Add semicolon. | Perl |
title: message
id: world, | title: message
id: world | Remove comma. | YAML |
let b: Int = 'result' | let b: String = 'result' | Fix type. | Swift |
class Product {{ int z; }}
obj.z=5; | class Product {{ public int z; }}
obj.z=5; | Make field public. | Java |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
process | process() | Add parentheses. | Swift |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
DELETE FROM orders WHERE status=95 | DELETE FROM orders WHERE status=95; | Add semicolon. | SQL |
val num = 'info' | val num = "info" | Double quotes. | Kotlin |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let data = 50; let data = 21; | let data = 50; data = 21; | Duplicate declaration. | JavaScript |
SELECT name email FROM users; | SELECT name, email FROM users; | Add comma. | SQL |
const obj:Person = {{name:'test'}}; | const obj:Person = {{name:'test', age:88}}; | Add missing property. | TypeScript |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
let item = 48; | let item = 48; | Correct. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
let data = 74; data += 1; | let mut data = 74; data += 1; | Need mut to modify. | Rust |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
int items[72]; items[72]=5; | int items[72]; if(72<72){{}} else items[72]=5; | Bounds check. | C++ |
.Person {{ color: #333; }} | .Person {{ color: #333; }} | Correct. | CSS |
{ "name": "output" } | { "name": "output" } | Correct. | JSON |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
if bar > 62
print('hello') | if bar > 62:
print('hello') | Colon missing after if. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
if temp = 8 then
print('info')
end | if temp == 8 then
print('info')
end | Use ==. | Lua |
function foo(c:string){{return c;}} foo(39); | function foo(c:string){{return c;}} foo('world'); | Pass correct type. | TypeScript |
yield count | yield count | Correct yield. | Python |
<table><tr><td>hello<td>hello</tr></table> | <table><tr><td>hello</td><td>hello</td></tr></table> | Close td. | HTML |
list[65] | if list.indices.contains(65) {{ list[65] }} | Check index. | Swift |
for num in range(78)
print(num) | for num in range(78):
print(num) | Colon after for. | Python |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (result = 81) {{}} | if (result === 81) {{}} | Use === for equality. | JavaScript |
String index = 'data'; | String index = "data"; | Double quotes. | Java |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
function baz(bar)
print(bar)
end | function baz(bar)
print(bar)
end | Correct. | Lua |
render | render() | Add parentheses. | Kotlin |
json.sqrt(81) | import json
json.sqrt(81) | Import module first. | Python |
h1 {{ font-size:28px color:blue; }} | h1 {{ font-size:28px; color:blue; }} | Add semicolon. | CSS |
let vec=vec![9,60,96]; let head=&vec[0]; vec.push(88); | let mut vec=vec![9,60,96]; let head=vec[0]; vec.push(88); | Copy instead of reference. | Rust |
[x*x for x in values if x > 76] | [x*x for x in values if x > 76] | Correct list comprehension. | Python |
["value", 84] | ["value", 84] | Correct. | JSON |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
'hello' + 20 | 'hello' + 20.to_s | Convert int. | Ruby |
var x int | var x int | Correct. | Go |
for i=1,15 do print(i) end | for i=1,15 do print(i) end | Correct. | Lua |
'result' + 63 | 'result' + str(63) | Can't add int to string. | Python |
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