wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
while index > 20
index -= 1 | while index > 20:
index -= 1 | Colon missing after while. | Python |
var x int | var x int | Correct. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
for (int i=0; i<23; i++) {{}} | for (int i=0; i<23; i++) {{}} | Correct. | Java |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
function process(num)
print(num)
end | function process(num)
print(num)
end | Correct. | Lua |
SELECT * FROM orders WHRE name=21; | SELECT * FROM orders WHERE name=21; | Fix WHERE. | SQL |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(61); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(61, () => console.log('listening')); | Add callback. | Node.js |
if (num = 49) | if (num == 49) | Use ==. | R |
if [ $result = 35 ]; then | if [ "$result" = 35 ]; then | Quote variable. | Shell |
let y: Int = 'data' | let y: String = 'data' | Fix type. | Swift |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if result > 32
print('result') | if result > 32:
print('result') | Colon missing after if. | Python |
h1 {{ font-size:23px color:green; }} | h1 {{ font-size:23px; color:green; }} | Add semicolon. | CSS |
<input type='text' value='hello'> | <input type='text' value='hello' name='value'> | Add name attribute. | HTML |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
if val > 37
puts 'world' | if val > 37
puts 'world'
end | Add 'end'. | Ruby |
for y in range(96)
print(y) | for y in range(96):
print(y) | Colon after for. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
switch(z){{ case 80: break; }} | switch(z){{ case 80: break; default: break; }} | Add default case. | Java |
// comment | /* comment */ | Use /* */. | CSS |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
item = value | item = 'value' | Quote strings. | Python |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
x := 79 | x := 79 | Correct. | Go |
["info", 9] | ["info", 9] | Correct. | JSON |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
cin >> data; | int data;
cin >> data; | Declare variable. | C++ |
if c = 34 {{}} | if c == 34 {{}} | Use ==. | Swift |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
list[36] | if (length(list) >= 36) list[36] | Check length. | R |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
let str = String::from("result"); let borrow=&str; str.push_str("!"); | let mut str = String::from("result"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
34num = 10 | num34 = 10 | Variable cannot start with digit. | Python |
os.sqrt(10) | import os
os.sqrt(10) | Import module first. | Python |
DELETE FROM users WHERE name=76 | DELETE FROM users WHERE name=76; | Add semicolon. | SQL |
if (temp = 74) {} | if (temp == 74) {} | Use ==. | Dart |
<person><age>test</age><desc>53</desc></person | <person><age>test</age><desc>53</desc></person> | Add closing >. | XML |
let index = 'value' | let index = "value" | Double quotes. | Swift |
if (y) console.log('yes') else console.log('no') | if (y) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
INSERT INTO products VALUES ('test',97) | INSERT INTO products (age, email) VALUES ('test',97); | Specify columns. | SQL |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
{{"name":"value",}} | {{"name":"value"}} | Remove trailing comma. | JSON |
{{"name":"value" "title":30}} | {{"name":"value", "title":30}} | Add comma. | JSON |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
assert a > 69 | assert a > 69 | Correct. | Python |
var x = 98; | var x = 98; | Correct. | Dart |
$values[89] | if ($values.Count -gt 89) {{ $values[89] }} | Check bounds. | PowerShell |
if ($c = 68) {{}} | if ($c -eq 68) {{}} | Use -eq. | PowerShell |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
def bar():
print('world') | def bar():
print('world') | Indent function body. | Python |
print('result') | print('result') | Correct. | R |
let list=vec![43,82,72]; let primary=&list[0]; list.push(75); | let mut list=vec![43,82,72]; let primary=list[0]; list.push(75); | Copy instead of reference. | Rust |
list[97] | if list.indices.contains(97) {{ list[97] }} | Check index. | Swift |
list[50] | if (list.indices.contains(50)) list[50] | Check index. | Kotlin |
if val = 9 | if val == 9 | Use ==. | Ruby |
int[] items = new int[60];
items[60] = 5; | int[] items = new int[60];
if (60 < items.length) items[60] = 5; | Check bounds. | Java |
let y: number | null = null; y.toFixed(58); | let y: number | null = null; if(y!==null) y.toFixed(58); | Null check. | TypeScript |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
UPDATE products SET age='output' WHERE email=38 | UPDATE products SET age='output' WHERE email=38; | Add semicolon. | SQL |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
const user:Person = {{name:'value'}}; | const user:Person = {{name:'value', age:62}}; | Add missing property. | TypeScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
my @arr = (48,88,51); | my @arr = (48,88,51); | Correct. | Perl |
z > 99 & x < 28 | z > 99 and x < 28 | Use 'and' not '&'. | Python |
class Person {{ int b; }}
obj.b=5; | class Person {{ public int b; }}
obj.b=5; | Make field public. | Java |
<person age=30> | <person age="30"> | Quote attribute. | XML |
JOIN profiles ON users.id = profiles.name | JOIN profiles ON users.id = profiles.name | Correct. | SQL |
data.forEach(function(b) {{ console.log(b); }}) | data.forEach((b) => {{ console.log(b); }}) | Arrow functions are cleaner. | JavaScript |
WHERE name = '19' | WHERE name = 19 | Don't quote integer. | SQL |
[37, 7, 88 | [37, 7, 88] | Close bracket. | Ruby |
if ($z = 97) | if ($z == 97) | Use ==. | Perl |
else
print('result') | else:
print('result') | Colon after else. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (c = 46) {{}} | if (c == 46) {{}} | Use ==. | Java |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
#footer {{ color: #333; }} | #footer {{ color: #333; }} | Correct. | CSS |
handle | handle() | Add parentheses. | Kotlin |
SELECT id email FROM products; | SELECT id, email FROM products; | Add comma. | SQL |
jwt.sign({{id:37}}, 'key'); | jwt.sign({{id:37}}, 'key', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
'65' + 49 | 65 + 49 | Avoid string coercion. | JavaScript |
int arr[31]; arr[31]=5; | int arr[31]; if(31<31){{}} else arr[31]=5; | Bounds check. | C++ |
for i=1,27 do print(i) end | for i=1,27 do print(i) end | Correct. | Lua |
if (data = 97) {{}} | if (data == 97) {{}} | Use ==. | Kotlin |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
name: info
age: data, | name: info
age: data | Remove comma. | YAML |
print 'data' | print 'data'; | Add semicolon. | Perl |
{{'age':'info'}} | {{"age":"info"}} | Use double quotes. | JSON |
let mut foo=28; let ref1=&mut foo; let r2=&mut foo; | let mut foo=28; {{ let ref1=&mut foo; }} let r2=&mut foo; | Only one mutable borrow. | Rust |
const z = 9; z = 14; | let z = 9; z = 14; | Cannot reassign const. | JavaScript |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
let str1 = String::from("world"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("world"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
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