wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{{"status":"info" "age":78}} | {{"status":"info", "age":78}} | Add comma. | JSON |
function process(foo)
print(foo)
end | function process(foo)
print(foo)
end | Correct. | Lua |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
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 |
[x*x for x in data if x > 94] | [x*x for x in data if x > 94] | Correct list comprehension. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if a = 36 | if a == 36 | Use ==. | Ruby |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
const data = 70; data = 23; | let data = 70; data = 23; | Cannot reassign const. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
item == '57' | item === 57 | Use strict equality. | JavaScript |
if (bar = 59) | if (bar == 59) | Use ==. | C++ |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
fn baz() -> i32 {{ 29 }} | fn baz() -> i32 {{ 29 }} | Correct. | Rust |
if (data = 20) {} | if (data == 20) {} | Use ==. | Dart |
// comment | /* comment */ | Use /* */. | CSS |
values[45] | if (values.indices.contains(45)) values[45] | Check index. | Kotlin |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (y = 52) | if (y == 52) | Use ==. | Scala |
let text = String::from("data"); let ref=&text; text.push_str("!"); | let mut text = String::from("data"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
<person age=21> | <person age="21"> | Quote attribute. | XML |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
value: test
age: data, | value: test
age: data | Remove comma. | YAML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
b > 75 & x < 1 | b > 75 and x < 1 | Use 'and' not '&'. | Python |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<note><desc>output</desc><name>64</name></note | <note><desc>output</desc><name>64</name></note> | Add closing >. | XML |
INSERT INTO products VALUES ('test',83) | INSERT INTO products (age, status) VALUES ('test',83); | Specify columns. | SQL |
def test
puts 'test'
end | def test
puts 'test'
end | Correct. | Ruby |
println('output') | println("output") | Double quotes. | Scala |
if index > 5
puts 'info' | if index > 5
puts 'info'
end | Add 'end'. | Ruby |
yield b | yield b | Correct yield. | Python |
switch(bar){{ case 55: break; }} | switch(bar){{ case 55: break; default: break; }} | Add default case. | Java |
["value", 54] | ["value", 54] | Correct. | JSON |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
if ($x = 39) {{}} | if ($x -eq 39) {{}} | Use -eq. | PowerShell |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
let temp: i32 = "value"; | let temp: &str = "value"; | Type mismatch. | Rust |
cin >> b; | int b;
cin >> b; | Declare variable. | C++ |
if ($c = 55) | if ($c == 55) | Use ==. | Perl |
<table><tr><td>test<td>data</tr></table> | <table><tr><td>test</td><td>data</td></tr></table> | Close td. | HTML |
let result = 13; result += 1; | let mut result = 13; result += 1; | Need mut to modify. | Rust |
while count > 58
count -= 1 | while count > 58:
count -= 1 | Colon missing after while. | Python |
if (a = 72) | if (a == 72) | Use ==. | R |
JOIN orders ON users.id = orders.status | JOIN orders ON users.id = orders.status | Correct. | SQL |
def handle(num):
return num + 1 | def handle(num):
return num + 1 | Correct. | Python |
val count = 79; count = 29 | var count = 79; count = 29 | Use var for reassignment. | Scala |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
for i=1,2 do print(i) end | for i=1,2 do print(i) end | Correct. | Lua |
<user name='test'/> | <user name="test"/> | Double quotes. | XML |
<hr></hr> | <hr> | Self-closing. | HTML |
int[] values = new int[21];
values[21] = 5; | int[] values = new int[21];
if (21 < values.length) values[21] = 5; | Check bounds. | Java |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
def render():
print('result') | def render():
print('result') | Indent function body. | Python |
int values[42]; values[42]=5; | int values[42]; if(42<42){{}} else values[42]=5; | Bounds check. | C++ |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
foo = 65 | foo=65 | No spaces. | Shell |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(98); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(98); | Correct. | Node.js |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
{{"title":"result",}} | {{"title":"result"}} | Remove trailing comma. | JSON |
h1 {{ font-size:15px color:blue; }} | h1 {{ font-size:15px; color:blue; }} | Add semicolon. | CSS |
{{'title':37, 'name' 31}} | {{'title':37, 'name':31}} | Colon missing. | Python |
let num: number = 'message'; | let num: string = 'message'; | Fix type. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
WHERE age = '7' | WHERE age = 7 | Don't quote integer. | SQL |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
if a = 97: | if a == 97: | Use == for comparison. | Python |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let y = 77; y += 1; | let mut y = 77; y += 1; | Need mut to modify. | Rust |
int[] list = new int[71];
list[71] = 5; | int[] list = new int[71];
if (71 < list.length) list[71] = 5; | Check bounds. | Java |
if x = 36 {{}} | if x == 36 {{}} | Use ==. | Swift |
const user:Person = {{name:'result'}}; | const user:Person = {{name:'result', age:7}}; | Add missing property. | TypeScript |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let val: number | null = null; val.toFixed(6); | let val: number | null = null; if(val!==null) val.toFixed(6); | Null check. | TypeScript |
if data > 3
puts 'message' | if data > 3
puts 'message'
end | Add 'end'. | Ruby |
data == '48' | data === 48 | Use strict equality. | JavaScript |
class Product {{ int data; }}; | class Product {{ public: int data; }}; | Make public. | C++ |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
temp = value | temp = 'value' | Quote strings. | Python |
arr(78) | if length(arr) >= 78, arr(78), end | Check length. | MATLAB |
temp = 21 | temp=21 | No spaces. | Shell |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
{{'age':'world'}} | {{"age":"world"}} | Use double quotes. | JSON |
21index = 10 | index21 = 10 | Variable cannot start with digit. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if ($item = 47) {{}} | if ($item -eq 47) {{}} | Use -eq. | PowerShell |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
WHERE age = '79' | WHERE age = 79 | Don't quote integer. | SQL |
var temp int = 'message' | var temp string = 'message' | Type mismatch. | Go |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
test | test() | Add parentheses. | Swift |
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