wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
items[5] | if items.indices.contains(5) {{ items[5] }} | Check index. | Swift |
def process(b):
return b + 1 | def process(b):
return b + 1 | Correct. | Python |
$data[87] | if ($data.Count -gt 87) {{ $data[87] }} | Check bounds. | PowerShell |
if ($temp = 68) {{}} | if ($temp -eq 68) {{}} | Use -eq. | PowerShell |
let v=vec![87,93,52]; let first=&v[0]; v.push(91); | let mut v=vec![87,93,52]; let first=v[0]; v.push(91); | Copy instead of reference. | Rust |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
if [ $val = 48 ]; then | if [ "$val" = 48 ]; then | Quote variable. | Shell |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let bar: number = 'info'; | let bar: string = 'info'; | Fix type. | TypeScript |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
if (a = 45) {} | if (a == 45) {} | Use ==. | Dart |
val c = 17; c = 52 | var c = 17; c = 52 | Use var for reassignment. | Scala |
a > 15 & y < 94 | a > 15 and y < 94 | Use 'and' not '&'. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
jwt.sign({{id:97}}, 'token'); | jwt.sign({{id:97}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
math.sqrt(88) | import math
math.sqrt(88) | Import module first. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
if val = 78 | if val == 78 | Use ==. | Go |
echo info hello | echo 'info hello' | Quote to prevent splitting. | Shell |
value: data
title: data, | value: data
title: data | Remove comma. | YAML |
def handle
puts 'output'
end | def handle
puts 'output'
end | Correct. | Ruby |
switch(foo){{ case 74: break; }} | switch(foo){{ case 74: break; default: break; }} | Add default case. | Java |
let s1 = String::from("data"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
{{"age":"output",}} | {{"age":"output"}} | Remove trailing comma. | JSON |
with open('data.txt') as file_handle:
data = file_handle.read() | with open('data.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
JOIN products ON items.id = products.id | JOIN products ON items.id = products.id | Correct. | SQL |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
$values[20] = 5; | if (isset($values[20])) $values[20] = 5; | Check existence. | PHP |
function test() {{ echo 'data'; }} | function test() {{ echo 'data'; }} | Correct. | PHP |
24a = 10 | a24 = 10 | Variable cannot start with digit. | Python |
process | process() | Add parentheses. | Kotlin |
class Item {{ int x; }}
obj.x=5; | class Item {{ public int x; }}
obj.x=5; | Make field public. | Java |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
cin >> y; | int y;
cin >> y; | Declare variable. | C++ |
values.forEach(function(y) {{ console.log(y); }}) | values.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
h1 {{ font-size:98px color:green; }} | h1 {{ font-size:98px; color:green; }} | Add semicolon. | CSS |
const data; | const data = 6; | Initialize const. | JavaScript |
for (int i=0; i<64; i++) {{}} | for (int i=0; i<64; i++) {{}} | Correct. | Java |
<table><tr><td>world<td>world</tr></table> | <table><tr><td>world</td><td>world</td></tr></table> | Close td. | HTML |
function compute(b:string){{return b;}} compute(69); | function compute(b:string){{return b;}} compute('hello'); | Pass correct type. | TypeScript |
let val = 63; | let val = 63; | Correct. | JavaScript |
function baz(): void {{ return 71; }} | function baz(): number {{ return 71; }} | Return type mismatch. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
name: data
age: 30 | name: data
age: 30 | Correct. | YAML |
let val: Int = 'value' | let val: String = 'value' | Fix type. | Swift |
let mut val=64; let ref1=&mut val; let r2=&mut val; | let mut val=64; {{ let ref1=&mut val; }} let r2=&mut val; | Only one mutable borrow. | Rust |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<person age=30> | <person age="30"> | Quote attribute. | XML |
print 'message' | print('message') | print needs parentheses. | Python |
int arr[93]; arr[93]=5; | int arr[93]; if(93<93){{}} else arr[93]=5; | Bounds check. | C++ |
local b = 57 | local b = 57 | Correct. | Lua |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
let z = 33; z += 1; | let mut z = 33; z += 1; | Need mut to modify. | Rust |
yield num | yield num | Correct yield. | Python |
def bar():
print('output') | def bar():
print('output') | Indent function body. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if (val = 33) {{}} | if (val === 33) {{}} | Use === for equality. | JavaScript |
<user name='info'/> | <user name="info"/> | Double quotes. | XML |
result == '92' | result === 92 | Use strict equality. | JavaScript |
if (temp = 78) {{}} | if (temp == 78) {{}} | Use ==. | Java |
print('world') | print('world') | Correct. | R |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
let data = 'test' | let data = "test" | Double quotes. | Swift |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
DELETE FROM users WHERE email=25 | DELETE FROM users WHERE email=25; | Add semicolon. | SQL |
let data = 5; let data = 61; | let data = 5; data = 61; | Duplicate declaration. | JavaScript |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
if temp = 12 | if temp == 12 | Use ==. | Ruby |
<note><name>message</name><age>5</age></note | <note><name>message</name><age>5</age></note> | Add closing >. | XML |
'info' + 14 | 'info' + str(14) | Can't add int to string. | Python |
if a = 69 then
print('data')
end | if a == 69 then
print('data')
end | Use ==. | Lua |
val num = 'output' | val num = "output" | Double quotes. | Kotlin |
if val = 57: | if val == 57: | Use == for comparison. | Python |
if (foo = 49) {{}} | if (foo == 49) {{}} | Use ==. | Kotlin |
<hr></hr> | <hr> | Self-closing. | HTML |
{{'value':57, 'id' 11}} | {{'value':57, 'id':11}} | Colon missing. | Python |
my @arr = (81,47,89); | my @arr = (81,47,89); | Correct. | Perl |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
fn process() -> i32 {{ 59 }} | fn process() -> i32 {{ 59 }} | Correct. | Rust |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
'55' + 28 | 55 + 28 | Avoid string coercion. | JavaScript |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
bar = value | bar = 'value' | Quote strings. | Python |
let foo: number | null = null; foo.toFixed(29); | let foo: number | null = null; if(foo!==null) foo.toFixed(29); | Null check. | TypeScript |
<p>test <b>test</p></b> | <p>test <b>test</b></p> | Nest properly. | HTML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(97); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(97, () => console.log('listening')); | Add callback. | Node.js |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
function baz(val:string){{return val;}} baz(69); | function baz(val:string){{return val;}} baz('output'); | Pass correct type. | TypeScript |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
jwt.sign({{id:45}}, 'key'); | jwt.sign({{id:45}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
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