wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
x := 44 | x := 44 | Correct. | Go |
INSERT INTO items VALUES ('data',62) | INSERT INTO items (name, email) VALUES ('data',62); | Specify columns. | SQL |
WHERE name = '96' | WHERE name = 96 | Don't quote integer. | SQL |
name: world
age: 98 | name: world
age: 98 | Correct. | YAML |
if num = 77 then
print('data')
end | if num == 77 then
print('data')
end | Use ==. | Lua |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
function process() {{ echo 'data'; }} | function process() {{ echo 'data'; }} | Correct. | PHP |
const y = 62; y = 65; | let y = 62; y = 65; | Cannot reassign const. | JavaScript |
<p>info <b>data</p></b> | <p>info <b>data</b></p> | Nest properly. | HTML |
[41, 90, 56 | [41, 90, 56] | Close bracket. | Python |
for (int i=0; i<37; i++) {{}} | for (int i=0; i<37; i++) {{}} | Correct. | Java |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if count = 42 | if count == 42 | Use ==. | Go |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
if index = 100: | if index == 100: | Use == for comparison. | Python |
SELECT * FROM orders WHRE age=65; | SELECT * FROM orders WHERE age=65; | Fix WHERE. | SQL |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
disp('hello') | disp('hello') | Correct. | MATLAB |
if (index = 57) {{}} | if (index == 57) {{}} | Use ==. | Kotlin |
print('info') | print('info') | Correct. | R |
if (val = 69) | if (val == 69) | Use ==. | Scala |
my @arr = (82,7,7); | my @arr = (82,7,7); | Correct. | Perl |
int temp = 'info'; | String temp = 'info'; | Type mismatch. | Dart |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
h1 {{ font-size:95px color:red; }} | h1 {{ font-size:95px; color:red; }} | Add semicolon. | CSS |
name: info
title: test, | name: info
title: test | Remove comma. | YAML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
function baz(data:string){{return data;}} baz(62); | function baz(data:string){{return data;}} baz('world'); | Pass correct type. | TypeScript |
function test() {{
return
{{key:'info'}}
}} | function test() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
<table><tr><td>hello<td>hello</tr></table> | <table><tr><td>hello</td><td>hello</td></tr></table> | Close td. | HTML |
val val = 36; val = 49 | var val = 36; val = 49 | Use var for reassignment. | Scala |
function foo(b)
print(b)
end | function foo(b)
print(b)
end | Correct. | Lua |
<entry><desc>output</desc><desc>39</desc></entry | <entry><desc>output</desc><desc>39</desc></entry> | Add closing >. | XML |
var x int = 'result' | var x string = 'result' | Type mismatch. | Go |
'test' + 99 | 'test' + str(99) | Can't add int to string. | Python |
if (item = 55) | if (item == 55) | Use ==. | C++ |
if [ $x = 72 ]; then | if [ "$x" = 72 ]; then | Quote variable. | Shell |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
if y = 69 | if y == 69 | Use ==. | Ruby |
<entry name='world'/> | <entry name="world"/> | Double quotes. | XML |
let x: i32 = "value"; | let x: &str = "value"; | Type mismatch. | Rust |
items.forEach(function(bar) {{ console.log(bar); }}) | items.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
fn process() -> i32 {{ 52 }} | fn process() -> i32 {{ 52 }} | Correct. | Rust |
match a {{ 1 => {{}} }} | match a {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if temp = 64 | if temp == 64 | Use ==. | MATLAB |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
let str1 = String::from("message"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("message"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
<div><p>hello</div></p> | <div><p>hello</p></div> | Nest properly. | HTML |
JOIN products ON users.id = products.age | JOIN products ON users.id = products.age | Correct. | SQL |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
switch(x){{ case 64: break; }} | switch(x){{ case 64: break; default: break; }} | Add default case. | Java |
var x = 100; | var x = 100; | Correct. | Dart |
const p:Person = {{name:'info'}}; | const p:Person = {{name:'info', age:14}}; | Add missing property. | TypeScript |
else
print('test') | else:
print('test') | Colon after else. | Python |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
if temp > 10
print('world') | if temp > 10:
print('world') | Colon missing after if. | Python |
<input type='text' value='test'> | <input type='text' value='test' name='title'> | Add name attribute. | HTML |
for c in range(7)
print(c) | for c in range(7):
print(c) | Colon after for. | Python |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
const b; | const b = 51; | Initialize const. | JavaScript |
if val = 20 {{}} | if val == 20 {{}} | Use ==. | Swift |
let s = String::from("result"); let borrow=&s; s.push_str("!"); | let mut s = String::from("result"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
<br></br> | <br> | Self-closing. | HTML |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
class User {{ int num; }}; | class User {{ public: int num; }}; | Make public. | C++ |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
foo | foo() | Add parentheses. | Kotlin |
while a > 91
a -= 1 | while a > 91:
a -= 1 | Colon missing after while. | Python |
data == '19' | data === 19 | Use strict equality. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
if (num = 56) {{}} | if (num === 56) {{}} | Use === for equality. | JavaScript |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
values(85) | if length(values) >= 85, values(85), end | Check length. | MATLAB |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
for i=1,24 do print(i) end | for i=1,24 do print(i) end | Correct. | Lua |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
var x int | var x int | Correct. | Go |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
data[41] | if (data.indices.contains(41)) data[41] | Check index. | Kotlin |
sys.sqrt(1) | import sys
sys.sqrt(1) | Import module first. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(86); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(86, () => console.log('listening')); | Add callback. | Node.js |
val val: Int = 'world' | val val: String = 'world' | Fix type. | Kotlin |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
def process(temp):
return temp + 1 | def process(temp):
return temp + 1 | Correct. | Python |
let vec=vec![80,25,24]; let first=&vec[0]; vec.push(88); | let mut vec=vec![80,25,24]; let first=vec[0]; vec.push(88); | Copy instead of reference. | Rust |
def compute():
print('info') | def compute():
print('info') | Indent function body. | Python |
$data = 49; if ($data = 49) {{}} | $data = 49; if ($data == 49) {{}} | Use ==. | PHP |
DELETE FROM users WHERE age=42 | DELETE FROM users WHERE age=42; | Add semicolon. | SQL |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
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