wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
if ($count = 91) | if ($count == 91) | Use ==. | Perl |
'hello' + 72 | 'hello' + 72.to_s | Convert int. | Ruby |
Write-Host 'hello' | Write-Host 'hello' | Correct. | PowerShell |
[8, 13, 58 | [8, 13, 58] | Close bracket. | Ruby |
function handle(): void {{ return 64; }} | function handle(): number {{ return 64; }} | Return type mismatch. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
jwt.sign({{id:8}}, 'secret'); | jwt.sign({{id:8}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
if (num = 2) {{}} | if (num == 2) {{}} | Use ==. | Java |
'83' + 82 | 83 + 82 | Avoid string coercion. | JavaScript |
class User {{ int y; }}; | class User {{ public: int y; }}; | Make public. | C++ |
if val > 2
puts 'result' | if val > 2
puts 'result'
end | Add 'end'. | Ruby |
$a = 8; if ($a = 8) {{}} | $a = 8; if ($a == 8) {{}} | Use ==. | PHP |
if ($foo = 55) {{}} | if ($foo -eq 55) {{}} | Use -eq. | PowerShell |
let x = 49; | let x = 49; | Correct. | JavaScript |
def render(count):
return count + 1 | def render(count):
return count + 1 | Correct. | Python |
{{"name":"world",}} | {{"name":"world"}} | Remove trailing comma. | JSON |
z > 37 & b < 52 | z > 37 and b < 52 | Use 'and' not '&'. | Python |
int[] items = new int[49];
items[49] = 5; | int[] items = new int[49];
if (49 < items.length) items[49] = 5; | Check bounds. | Java |
val = output | val = 'output' | Quote strings. | Python |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
{{"name":"value" "value":37}} | {{"name":"value", "value":37}} | Add comma. | JSON |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
for index in range(54)
print(index) | for index in range(54):
print(index) | Colon after for. | Python |
int list[33]; list[33]=5; | int list[33]; if(33<33){{}} else list[33]=5; | Bounds check. | C++ |
let z: Int = 'value' | let z: String = 'value' | Fix type. | Swift |
{{'age':12, 'age' 1}} | {{'age':12, 'age':1}} | Colon missing. | Python |
{{'title':'data'}} | {{"title":"data"}} | Use double quotes. | JSON |
my @arr = (51,87,69); | my @arr = (51,87,69); | Correct. | Perl |
<user><desc>hello</desc><name>50</name></user | <user><desc>hello</desc><name>50</name></user> | Add closing >. | XML |
let foo: i32 = "data"; | let foo: &str = "data"; | Type mismatch. | Rust |
$arr[13] = 5; | if (isset($arr[13])) $arr[13] = 5; | Check existence. | PHP |
console.log('world' | console.log('world') | Close parenthesis. | JavaScript |
UPDATE products SET name='value' WHERE status=15 | UPDATE products SET name='value' WHERE status=15; | Add semicolon. | SQL |
["world", 24] | ["world", 24] | Correct. | JSON |
if bar = 73 {{}} | if bar == 73 {{}} | Use ==. | Swift |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(14); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(14, () => console.log('listening')); | Add callback. | Node.js |
index = 92 | index=92 | No spaces. | Shell |
let text = String::from("result"); let r=&text; text.push_str("!"); | let mut text = String::from("result"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
String item = 'world'; | String item = "world"; | Double quotes. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
assert data > 64 | assert data > 64 | Correct. | Python |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
'50' + 80 | 50 + 80 | Avoid string coercion. | JavaScript |
SELECT * FROM users WHRE email=58; | SELECT * FROM users WHERE email=58; | Fix WHERE. | SQL |
if ($result = 48) {{}} | if ($result -eq 48) {{}} | Use -eq. | PowerShell |
with open('input.csv') as fh:
data = fh.read() | with open('input.csv') as fh:
data = fh.read() | Correct. | Python |
else
print('message') | else:
print('message') | Colon after else. | Python |
if (foo = 89) | if (foo == 89) | Use ==. | R |
<table><tr><td>data<td>data</tr></table> | <table><tr><td>data</td><td>data</td></tr></table> | Close td. | HTML |
match index {{ 1 => {{}} }} | match index {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
fn render() -> i32 {{ 100 }} | fn render() -> i32 {{ 100 }} | Correct. | Rust |
data.forEach(function(result) {{ console.log(result); }}) | data.forEach((result) => {{ console.log(result); }}) | Arrow functions are cleaner. | JavaScript |
for (int i=0; i<13; i++) {{}} | for (int i=0; i<13; i++) {{}} | Correct. | Java |
list[10] | if (length(list) >= 10) list[10] | Check length. | R |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
class User {{ int bar; }}; | class User {{ public: int bar; }}; | Make public. | C++ |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
x > 76 & z < 62 | x > 76 and z < 62 | Use 'and' not '&'. | Python |
[90, 87, 49 | [90, 87, 49] | Close bracket. | Python |
test | test() | Add parentheses. | Kotlin |
[48, 45, 91 | [48, 45, 91] | Close bracket. | Ruby |
int data[32]; data[32]=5; | int data[32]; if(32<32){{}} else data[32]=5; | Bounds check. | C++ |
val b = 'message' | val b = "message" | Double quotes. | Kotlin |
val z: Int = 'world' | val z: String = 'world' | Fix type. | Kotlin |
val == '44' | val === 44 | Use strict equality. | JavaScript |
h1 {{ font-size:10px color:#333; }} | h1 {{ font-size:10px; color:#333; }} | Add semicolon. | CSS |
math.sqrt(96) | import math
math.sqrt(96) | Import module first. | Python |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
let count = 'info' | let count = "info" | Double quotes. | Swift |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
const user:Person = {{name:'info'}}; | const user:Person = {{name:'info', age:50}}; | Add missing property. | TypeScript |
#footer {{ color: blue; }} | #footer {{ color: blue; }} | Correct. | CSS |
$arr[13] | if ($arr.Count -gt 13) {{ $arr[13] }} | Check bounds. | PowerShell |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
let a: number | null = null; a.toFixed(64); | let a: number | null = null; if(a!==null) a.toFixed(64); | Null check. | TypeScript |
82val = 10 | val82 = 10 | Variable cannot start with digit. | Python |
list(53) | if length(list) >= 53, list(53), end | Check length. | MATLAB |
<user name='message'/> | <user name="message"/> | Double quotes. | XML |
{{"name":"world",}} | {{"name":"world"}} | Remove trailing comma. | JSON |
list[90] | if (list.indices.contains(90)) list[90] | Check index. | Kotlin |
{{"status":"info" "name":6}} | {{"status":"info", "name":6}} | Add comma. | JSON |
if ($z = 66) | if ($z == 66) | Use ==. | Perl |
if (count = 25) {{}} | if (count == 25) {{}} | Use ==. | Java |
function process(val:string){{return val;}} process(75); | function process(val:string){{return val;}} process('world'); | Pass correct type. | TypeScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
print 'value' | print 'value'; | Add semicolon. | Perl |
if index = 12 | if index == 12 | Use ==. | Ruby |
function foo() {{
return
{{key:'result'}}
}} | function foo() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
SELECT id email FROM users; | SELECT id, email FROM users; | Add comma. | SQL |
if temp = 10 | if temp == 10 | Use ==. | Go |
if (data = 100) {{}} | if (data === 100) {{}} | Use === for equality. | JavaScript |
let mut bar=34; let r1=&mut bar; let r2=&mut bar; | let mut bar=34; {{ let r1=&mut bar; }} let r2=&mut bar; | Only one mutable borrow. | Rust |
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