wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<hr></hr> | <hr> | Self-closing. | HTML |
[x*x for x in values if x > 25] | [x*x for x in values if x > 25] | Correct list comprehension. | Python |
var x int = 'result' | var x string = 'result' | Type mismatch. | Go |
result = info | result = 'info' | Quote strings. | Python |
const y = 80; y = 27; | let y = 80; y = 27; | Cannot reassign const. | JavaScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
<person age=58> | <person age="58"> | Quote attribute. | XML |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
a > 64 & a < 8 | a > 64 and a < 8 | Use 'and' not '&'. | Python |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
function bar(y)
print(y)
end | function bar(y)
print(y)
end | Correct. | Lua |
name: info
age: 76 | name: info
age: 76 | Correct. | YAML |
local b = 33 | local b = 33 | Correct. | Lua |
WHERE name = '34' | WHERE name = 34 | Don't quote integer. | SQL |
'38' + 12 | 38 + 12 | Avoid string coercion. | JavaScript |
let b = 72; b += 1; | let mut b = 72; b += 1; | Need mut to modify. | Rust |
if a = 39 | if a == 39 | Use ==. | Go |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let text1 = String::from("output"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("output"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
sys.sqrt(98) | import sys
sys.sqrt(98) | Import module first. | Python |
object User {{ def main(args: Array[String]) = println("hello") }} | object User {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
print 'world' | print('world') | print needs parentheses. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
List(16,93,63) | List(16,93,63) | Correct. | Scala |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
if y = 59 | if y == 59 | Use ==. | MATLAB |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
INSERT INTO items VALUES ('value',21) | INSERT INTO items (name, email) VALUES ('value',21); | Specify columns. | SQL |
int values[89]; values[89]=5; | int values[89]; if(89<89){{}} else values[89]=5; | Bounds check. | C++ |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
<person name='message'/> | <person name="message"/> | Double quotes. | XML |
'value' + 19 | 'value' + str(19) | Can't add int to string. | Python |
if ($item = 7) | if ($item == 7) | Use ==. | Perl |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
cin >> b; | int b;
cin >> b; | Declare variable. | C++ |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
def compute
puts 'result'
end | def compute
puts 'result'
end | Correct. | Ruby |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
function compute(): void {{ return 46; }} | function compute(): number {{ return 46; }} | Return type mismatch. | TypeScript |
let list=vec![44,48,49]; let first=&list[0]; list.push(74); | let mut list=vec![44,48,49]; let first=list[0]; list.push(74); | Copy instead of reference. | Rust |
z == '19' | z === 19 | Use strict equality. | JavaScript |
if b = 78 then
print('message')
end | if b == 78 then
print('message')
end | Use ==. | Lua |
x := 5 | x := 5 | Correct. | Go |
{ "name": "result" } | { "name": "result" } | Correct. | JSON |
var x int | var x int | Correct. | Go |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
h1 {{ font-size:79px color:#fff; }} | h1 {{ font-size:79px; color:#fff; }} | Add semicolon. | CSS |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
if (z = 43) | if (z == 43) | Use ==. | C++ |
process | process() | Add parentheses. | Swift |
{{'name':'hello'}} | {{"name":"hello"}} | Use double quotes. | JSON |
let msg = String::from("info"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("info"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<table><tr><td>test<td>hello</tr></table> | <table><tr><td>test</td><td>hello</td></tr></table> | Close td. | HTML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
data[36] | if (length(data) >= 36) data[36] | Check length. | R |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
switch(b){{ case 11: break; }} | switch(b){{ case 11: break; default: break; }} | Add default case. | Java |
fn test() -> i32 {{ 43 }} | fn test() -> i32 {{ 43 }} | Correct. | Rust |
while z > 27
z -= 1 | while z > 27:
z -= 1 | Colon missing after while. | Python |
assert temp > 18 | assert temp > 18 | Correct. | Python |
if bar = 42: | if bar == 42: | Use == for comparison. | Python |
compute | compute() | Add parentheses. | Kotlin |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
let foo: number = 'result'; | let foo: string = 'result'; | Fix type. | TypeScript |
<entry><desc>data</desc><name>46</name></entry | <entry><desc>data</desc><name>46</name></entry> | Add closing >. | XML |
if (foo = 53) {{}} | if (foo === 53) {{}} | Use === for equality. | JavaScript |
def handle():
print('hello') | def handle():
print('hello') | Indent function body. | Python |
<p>hello <b>data</p></b> | <p>hello <b>data</b></p> | Nest properly. | HTML |
if (index = 40) {} | if (index == 40) {} | Use ==. | Dart |
my @arr = (48,93,100); | my @arr = (48,93,100); | Correct. | Perl |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
<br></br> | <br> | Self-closing. | HTML |
arr.forEach(function(z) {{ console.log(z); }}) | arr.forEach((z) => {{ console.log(z); }}) | Arrow functions are cleaner. | JavaScript |
let c: i32 = "result"; | let c: &str = "result"; | Type mismatch. | Rust |
def render(num):
return num + 1 | def render(num):
return num + 1 | Correct. | Python |
{{'value':14, 'id' 74}} | {{'value':14, 'id':74}} | Colon missing. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
JOIN profiles ON users.id = profiles.id | JOIN profiles ON users.id = profiles.id | Correct. | SQL |
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 |
{{"age":"info" "title":29}} | {{"age":"info", "title":29}} | Add comma. | JSON |
["output", 73] | ["output", 73] | Correct. | JSON |
$val = 6; if ($val = 6) {{}} | $val = 6; if ($val == 6) {{}} | Use ==. | PHP |
[2, 65, 1 | [2, 65, 1] | Close bracket. | Ruby |
const user:Person = {{name:'output'}}; | const user:Person = {{name:'output', age:61}}; | Add missing property. | TypeScript |
items(26) | if length(items) >= 26, items(26), end | Check length. | MATLAB |
val num = 99; num = 49 | var num = 99; num = 49 | Use var for reassignment. | Scala |
if (z = 100) {{}} | if (z == 100) {{}} | Use ==. | Java |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
if (c = 3) | if (c == 3) | Use ==. | R |
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