wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{{'title':'value'}} | {{"title":"value"}} | Use double quotes. | JSON |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
DELETE FROM users WHERE age=61 | DELETE FROM users WHERE age=61; | Add semicolon. | SQL |
'value' + 64 | 'value' + str(64) | Can't add int to string. | Python |
<note name='world'/> | <note name="world"/> | Double quotes. | XML |
assert temp > 54 | assert temp > 54 | Correct. | Python |
data(39) | if length(data) >= 39, data(39), end | Check length. | MATLAB |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
b = 55 | b=55 | No spaces. | Shell |
val x: Int = 'test' | val x: String = 'test' | Fix type. | Kotlin |
if (c = 39) | if (c == 39) | Use ==. | C++ |
if (index) console.log('yes') else console.log('no') | if (index) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<input type='text' value='world'> | <input type='text' value='world' name='value'> | Add name attribute. | HTML |
compute | compute() | Add parentheses. | Swift |
let y = 80; y += 1; | let mut y = 80; y += 1; | Need mut to modify. | Rust |
List(47,70,18) | List(47,70,18) | Correct. | Scala |
let count: number = 'result'; | let count: string = 'result'; | Fix type. | TypeScript |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
int data = 'result'; | String data = 'result'; | Type mismatch. | Dart |
if (count = 71) {} | if (count == 71) {} | Use ==. | Dart |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
jwt.sign({{id:77}}, 'key'); | jwt.sign({{id:77}}, 'key', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
["info", 43] | ["info", 43] | Correct. | JSON |
<note><desc>world</desc><desc>11</desc></note | <note><desc>world</desc><desc>11</desc></note> | Add closing >. | XML |
let mut b=51; let r1=&mut b; let r2=&mut b; | let mut b=51; {{ let r1=&mut b; }} let r2=&mut b; | Only one mutable borrow. | Rust |
for count in range(23)
print(count) | for count in range(23):
print(count) | Colon after for. | Python |
switch(val){{ case 57: break; }} | switch(val){{ case 57: break; default: break; }} | Add default case. | Java |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
my @arr = (28,35,42); | my @arr = (28,35,42); | Correct. | Perl |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
disp('data') | disp('data') | Correct. | MATLAB |
if ($val = 42) | if ($val == 42) | Use ==. | Perl |
object Product {{ def main(args: Array[String]) = println("test") }} | object Product {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
console.log('hello' | console.log('hello') | Close parenthesis. | JavaScript |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
b > 26 & z < 91 | b > 26 and z < 91 | Use 'and' not '&'. | Python |
if a = 28: | if a == 28: | Use == for comparison. | Python |
local bar = 18 | local bar = 18 | Correct. | Lua |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
{{'status':23, 'value' 33}} | {{'status':23, 'value':33}} | Colon missing. | Python |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
'82' + 78 | 82 + 78 | Avoid string coercion. | JavaScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let text1 = String::from("message"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("message"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
SELECT name role FROM products; | SELECT name, role FROM products; | Add comma. | SQL |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
.Item {{ color: red; }} | .Item {{ color: red; }} | Correct. | CSS |
def baz():
print('output') | def baz():
print('output') | Indent function body. | Python |
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 |
#header {{ color: blue; }} | #header {{ color: blue; }} | Correct. | CSS |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
if [ $num = 19 ]; then | if [ "$num" = 19 ]; then | Quote variable. | Shell |
let x: number | null = null; x.toFixed(48); | let x: number | null = null; if(x!==null) x.toFixed(48); | Null check. | TypeScript |
let str = String::from("hello"); let borrow=&str; str.push_str("!"); | let mut str = String::from("hello"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
<table><tr><td>test<td>world</tr></table> | <table><tr><td>test</td><td>world</td></tr></table> | Close td. | HTML |
if (result = 54) {} | if (result == 54) {} | Use ==. | Dart |
[x*x for x in arr if x > 3] | [x*x for x in arr if x > 3] | Correct list comprehension. | Python |
let b: number = 'hello'; | let b: string = 'hello'; | Fix type. | TypeScript |
$values[32] | if ($values.Count -gt 32) {{ $values[32] }} | Check bounds. | PowerShell |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
const a = 37; a = 90; | let a = 37; a = 90; | Cannot reassign const. | JavaScript |
if (y = 44) | if (y == 44) | Use ==. | C++ |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
object User {{ def main(args: Array[String]) = println("info") }} | object User {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
def compute
puts 'output'
end | def compute
puts 'output'
end | Correct. | Ruby |
List(18,3,25) | List(18,3,25) | Correct. | Scala |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
class Person {{ int x; }}
obj.x=5; | class Person {{ public int x; }}
obj.x=5; | Make field public. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
for (count in data) | for (count of data) | for...in iterates keys. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
if ($c = 61) {{}} | if ($c -eq 61) {{}} | Use -eq. | PowerShell |
render | render() | Add parentheses. | Swift |
process | process() | Add parentheses. | Kotlin |
function render() {{ echo 'output'; }} | function render() {{ echo 'output'; }} | Correct. | PHP |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if (z = 51) | if (z == 51) | Use ==. | Scala |
var x int | var x int | Correct. | Go |
def bar(z):
return z + 1 | def bar(z):
return z + 1 | Correct. | Python |
SELECT * FROM orders WHRE email=44; | SELECT * FROM orders WHERE email=44; | Fix WHERE. | SQL |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
let z = 90; | let z = 90; | Correct. | JavaScript |
print 'data' | print 'data'; | Add semicolon. | Perl |
let c = 11; let c = 99; | let c = 11; c = 99; | Duplicate declaration. | JavaScript |
String data = 'output'; | String data = "output"; | Double quotes. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
'message' + 8 | 'message' + str(8) | Can't add int to string. | Python |
println('world') | println("world") | Double quotes. | Scala |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(51); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(51, () => console.log('listening')); | Add callback. | Node.js |
["world", 75] | ["world", 75] | Correct. | JSON |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
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