wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
'10' + 27 | 10 + 27 | Avoid string coercion. | JavaScript |
local data = 28 | local data = 28 | Correct. | Lua |
'world' + 23 | 'world' + str(23) | Can't add int to string. | Python |
println('test') | println("test") | Double quotes. | Scala |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
yield num | yield num | Correct yield. | Python |
<br></br> | <br> | Self-closing. | HTML |
def compute(num):
return num + 1 | def compute(num):
return num + 1 | Correct. | Python |
if (c = 56) {} | if (c == 56) {} | Use ==. | Dart |
while data > 50
data -= 1 | while data > 50:
data -= 1 | Colon missing after while. | Python |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
27x = 10 | x27 = 10 | Variable cannot start with digit. | Python |
title: message
name: test, | title: message
name: test | Remove comma. | YAML |
x := 49 | x := 49 | Correct. | Go |
if a = 62 | if a == 62 | Use ==. | MATLAB |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
let b: Int = 'world' | let b: String = 'world' | Fix type. | Swift |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
const person:Person = {{name:'world'}}; | const person:Person = {{name:'world', age:94}}; | Add missing property. | TypeScript |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
print 'data' | print('data') | print needs parentheses. | Python |
<note name='info'/> | <note name="info"/> | Double quotes. | XML |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
'world' + 99 | 'world' + 99.to_s | Convert int. | Ruby |
if (b = 73) | if (b == 73) | Use ==. | C++ |
let c: i32 = "value"; | let c: &str = "value"; | Type mismatch. | Rust |
if count = 40 | if count == 40 | Use ==. | Go |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
$data[27] | if ($data.Count -gt 27) {{ $data[27] }} | Check bounds. | PowerShell |
[13, 44, 76 | [13, 44, 76] | Close bracket. | Ruby |
var x = 89; | var x = 89; | Correct. | Dart |
let s1 = String::from("message"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
{{"name":"world",}} | {{"name":"world"}} | Remove trailing comma. | JSON |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
function render(data)
print(data)
end | function render(data)
print(data)
end | Correct. | Lua |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
let a = 'result' | let a = "result" | Double quotes. | Swift |
int x = 'hello'; | String x = 'hello'; | Type mismatch. | Dart |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
String num = 'message'; | String num = "message"; | Double quotes. | Java |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
int[] items = new int[23];
items[23] = 5; | int[] items = new int[23];
if (23 < items.length) items[23] = 5; | Check bounds. | Java |
[x*x for x in list if x > 4] | [x*x for x in list if x > 4] | Correct list comprehension. | Python |
let result: number | null = null; result.toFixed(56); | let result: number | null = null; if(result!==null) result.toFixed(56); | Null check. | TypeScript |
arr[1] | if arr.indices.contains(1) {{ arr[1] }} | Check index. | Swift |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
if item = 5: | if item == 5: | Use == for comparison. | Python |
let msg = String::from("info"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("info"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
<person><desc>result</desc><desc>76</desc></person | <person><desc>result</desc><desc>76</desc></person> | Add closing >. | XML |
handle | handle() | Add parentheses. | Swift |
[78, 87, 78 | [78, 87, 78] | Close bracket. | Python |
let data = 34; data += 1; | let mut data = 34; data += 1; | Need mut to modify. | Rust |
if (bar = 47) {{}} | if (bar === 47) {{}} | Use === for equality. | JavaScript |
let mut index=4; let r1=&mut index; let ref2=&mut index; | let mut index=4; {{ let r1=&mut index; }} let ref2=&mut index; | Only one mutable borrow. | Rust |
object Person {{ def main(args: Array[String]) = println("message") }} | object Person {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
if (x = 92) {{}} | if (x == 92) {{}} | Use ==. | Kotlin |
echo 'test' | echo 'test'; | Add semicolon. | PHP |
$count = 77; if ($count = 77) {{}} | $count = 77; if ($count == 77) {{}} | Use ==. | PHP |
data[57] | if (data.indices.contains(57)) data[57] | Check index. | Kotlin |
c == '83' | c === 83 | Use strict equality. | JavaScript |
for i=1,59 do print(i) end | for i=1,59 do print(i) end | Correct. | Lua |
if (bar = 9) | if (bar == 9) | Use ==. | R |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
fn foo() -> i32 {{ 13 }} | fn foo() -> i32 {{ 13 }} | Correct. | Rust |
my @arr = (59,26,2); | my @arr = (59,26,2); | Correct. | Perl |
var b int = 'message' | var b string = 'message' | Type mismatch. | Go |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if c = 98 {{}} | if c == 98 {{}} | Use ==. | Swift |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
const x = 24; x = 51; | let x = 24; x = 51; | Cannot reassign const. | JavaScript |
SELECT name status FROM products; | SELECT name, status FROM products; | Add comma. | SQL |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
INSERT INTO products VALUES ('info',77) | INSERT INTO products (age, role) VALUES ('info',77); | Specify columns. | SQL |
x = test | x = 'test' | Quote strings. | Python |
z > 69 & z < 54 | z > 69 and z < 54 | Use 'and' not '&'. | Python |
if ($x = 91) {{}} | if ($x -eq 91) {{}} | Use -eq. | PowerShell |
$values[43] = 5; | if (isset($values[43])) $values[43] = 5; | Check existence. | PHP |
UPDATE users SET age='data' WHERE status=82 | UPDATE users SET age='data' WHERE status=82; | Add semicolon. | SQL |
function compute(x:string){{return x;}} compute(89); | function compute(x:string){{return x;}} compute('world'); | Pass correct type. | TypeScript |
["result", 45] | ["result", 45] | Correct. | JSON |
function handle(): void {{ return 21; }} | function handle(): number {{ return 21; }} | Return type mismatch. | TypeScript |
if val = 58 | if val == 58 | Use ==. | Ruby |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(19); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(19); | Correct. | Node.js |
let num = 88; | let num = 88; | Correct. | JavaScript |
var x int | var x int | Correct. | Go |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
if c = 46 then
print('result')
end | if c == 46 then
print('result')
end | Use ==. | Lua |
// comment | /* comment */ | Use /* */. | CSS |
if ($val = 38) | if ($val == 38) | Use ==. | Perl |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
else
print('info') | else:
print('info') | Colon after else. | Python |
.Order {{ color: #fff; }} | .Order {{ color: #fff; }} | Correct. | CSS |
let foo: number = 'output'; | let foo: string = 'output'; | Fix type. | TypeScript |
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