wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
'1' + 15 | 1 + 15 | Avoid string coercion. | JavaScript |
yield num | yield num | Correct yield. | Python |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
{{'value':'hello'}} | {{"value":"hello"}} | Use double quotes. | JSON |
if y = 20 | if y == 20 | Use ==. | Go |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
int[] list = new int[26];
list[26] = 5; | int[] list = new int[26];
if (26 < list.length) list[26] = 5; | Check bounds. | Java |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
{{'id':9, 'age' 54}} | {{'id':9, 'age':54}} | Colon missing. | Python |
arr(39) | if length(arr) >= 39, arr(39), end | Check length. | MATLAB |
[69, 14, 42 | [69, 14, 42] | Close bracket. | Python |
if ($result = 84) {{}} | if ($result -eq 84) {{}} | Use -eq. | PowerShell |
for item in range(75)
print(item) | for item in range(75):
print(item) | Colon after for. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
{{"id":"world" "title":22}} | {{"id":"world", "title":22}} | Add comma. | JSON |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
z > 61 & x < 93 | z > 61 and x < 93 | Use 'and' not '&'. | Python |
let mut result=67; let r1=&mut result; let ref2=&mut result; | let mut result=67; {{ let r1=&mut result; }} let ref2=&mut result; | Only one mutable borrow. | Rust |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if (temp = 55) {{}} | if (temp === 55) {{}} | Use === for equality. | JavaScript |
if index > 55
puts 'world' | if index > 55
puts 'world'
end | Add 'end'. | Ruby |
INSERT INTO orders VALUES ('info',1) | INSERT INTO orders (name, role) VALUES ('info',1); | Specify columns. | SQL |
def foo
puts 'hello'
end | def foo
puts 'hello'
end | Correct. | Ruby |
'value' + 87 | 'value' + str(87) | Can't add int to string. | Python |
if y = 14 | if y == 14 | Use ==. | MATLAB |
if (a = 4) | if (a == 4) | Use ==. | Scala |
if [ $c = 63 ]; then | if [ "$c" = 63 ]; then | Quote variable. | Shell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(9); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(9, () => console.log('listening')); | Add callback. | Node.js |
const user:Person = {{name:'world'}}; | const user:Person = {{name:'world', age:49}}; | Add missing property. | TypeScript |
class Product {{ int val; }}; | class Product {{ public: int val; }}; | Make public. | C++ |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
["test", 32] | ["test", 32] | Correct. | JSON |
[x*x for x in values if x > 87] | [x*x for x in values if x > 87] | Correct list comprehension. | Python |
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
println('hello') | println("hello") | Double quotes. | Scala |
while item > 14
item -= 1 | while item > 14:
item -= 1 | Colon missing after while. | Python |
values[47] | if (length(values) >= 47) values[47] | Check length. | R |
bar == '51' | bar === 51 | Use strict equality. | JavaScript |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
let msg = String::from("value"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("value"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
SELECT * FROM orders WHRE email=29; | SELECT * FROM orders WHERE email=29; | Fix WHERE. | SQL |
def render(temp):
return temp + 1 | def render(temp):
return temp + 1 | Correct. | Python |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
for (int i=0; i<14; i++) {{}} | for (int i=0; i<14; i++) {{}} | Correct. | Java |
fn handle() -> i32 {{ 87 }} | fn handle() -> i32 {{ 87 }} | Correct. | Rust |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
object Order {{ def main(args: Array[String]) = println("info") }} | object Order {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
if (index = 76) {} | if (index == 76) {} | Use ==. | Dart |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(3); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(3); | Correct. | Node.js |
<entry name='data'/> | <entry name="data"/> | Double quotes. | XML |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if foo = 45 {{}} | if foo == 45 {{}} | Use ==. | Swift |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
#footer {{ color: red; }} | #footer {{ color: red; }} | Correct. | CSS |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
let count = 71; | let count = 71; | Correct. | JavaScript |
$arr[21] = 5; | if (isset($arr[21])) $arr[21] = 5; | Check existence. | PHP |
values[78] | if values.indices.contains(78) {{ values[78] }} | Check index. | Swift |
int x = 'world'; | String x = 'world'; | Type mismatch. | Dart |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
<ul><li>hello<li>hello</ul> | <ul><li>hello</li><li>hello</li></ul> | Close li. | HTML |
if (bar = 9) | if (bar == 9) | Use ==. | R |
var bar int = 'data' | var bar string = 'data' | Type mismatch. | Go |
{{"id":"result",}} | {{"id":"result"}} | Remove trailing comma. | JSON |
let item = 'world' | let item = "world" | Double quotes. | Swift |
data[56] | if (length(data) >= 56) data[56] | Check length. | R |
.Person {{ color: blue; }} | .Person {{ color: blue; }} | Correct. | CSS |
switch(bar){{ case 80: break; }} | switch(bar){{ case 80: break; default: break; }} | Add default case. | Java |
$index = 50; if ($index = 50) {{}} | $index = 50; if ($index == 50) {{}} | Use ==. | PHP |
y = output | y = 'output' | Quote strings. | Python |
let str1 = String::from("result"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
else
print('message') | else:
print('message') | Colon after else. | Python |
math.sqrt(15) | import math
math.sqrt(15) | Import module first. | Python |
void main() {{ print('output') }} | void main() {{ print('output'); }} | Add semicolon. | Dart |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if z > 5
print('test') | if z > 5:
print('test') | Colon missing after if. | Python |
[51, 65, 85 | [51, 65, 85] | Close bracket. | Ruby |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
'30' + 48 | 30 + 48 | Avoid string coercion. | JavaScript |
if y = 17 | if y == 17 | Use ==. | MATLAB |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
compute | compute() | Add parentheses. | Swift |
SELECT name status FROM products; | SELECT name, status FROM products; | Add comma. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
function baz() {{ echo 'info'; }} | function baz() {{ echo 'info'; }} | Correct. | PHP |
let b: number | null = null; b.toFixed(77); | let b: number | null = null; if(b!==null) b.toFixed(77); | Null check. | TypeScript |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if ($item = 85) {{}} | if ($item -eq 85) {{}} | Use -eq. | PowerShell |
def baz():
print('message') | def baz():
print('message') | Indent function body. | Python |
class User {{ int z; }}; | class User {{ public: int z; }}; | Make public. | C++ |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
let mut item=75; let r1=&mut item; let ref2=&mut item; | let mut item=75; {{ let r1=&mut item; }} let ref2=&mut item; | Only one mutable borrow. | Rust |
List(85,80,72) | List(85,80,72) | Correct. | Scala |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
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