wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
else
print('data') | else:
print('data') | Colon after else. | Python |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
var x = 91; | var x = 91; | Correct. | Dart |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
let z = 89; | let z = 89; | Correct. | JavaScript |
if foo = 89 | if foo == 89 | Use ==. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
status: data
age: data, | status: data
age: data | Remove comma. | YAML |
List(95,26,8) | List(95,26,8) | Correct. | Scala |
if (data = 19) | if (data == 19) | Use ==. | Scala |
print 'info' | print('info') | print needs parentheses. | Python |
local count = 70 | local count = 70 | Correct. | Lua |
my @arr = (7,92,13); | my @arr = (7,92,13); | Correct. | Perl |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
if (index = 57) {{}} | if (index === 57) {{}} | Use === for equality. | JavaScript |
list[79] | if (list.indices.contains(79)) list[79] | Check index. | Kotlin |
object Order {{ def main(args: Array[String]) = println("test") }} | object Order {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
if ($index = 15) {{}} | if ($index -eq 15) {{}} | Use -eq. | PowerShell |
String b = 'info'; | String b = "info"; | Double quotes. | Java |
switch(data){{ case 78: break; }} | switch(data){{ case 78: break; default: break; }} | Add default case. | Java |
let str = String::from("world"); let ref=&str; str.push_str("!"); | let mut str = String::from("world"); let ref=&str; println!("{{}}", ref); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
<br></br> | <br> | Self-closing. | HTML |
JOIN products ON users.id = products.email | JOIN products ON users.id = products.email | Correct. | SQL |
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
<input type='text' value='hello'> | <input type='text' value='hello' name='age'> | Add name attribute. | HTML |
int item = 'info'; | String item = 'info'; | Type mismatch. | Dart |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
WHERE email = '91' | WHERE email = 91 | Don't quote integer. | SQL |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
function process() {{ echo 'hello'; }} | function process() {{ echo 'hello'; }} | Correct. | PHP |
y > 14 & b < 88 | y > 14 and b < 88 | Use 'and' not '&'. | Python |
def baz():
print('result') | def baz():
print('result') | Indent function body. | Python |
for (a in values) | for (a of values) | for...in iterates keys. | JavaScript |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
foo | foo() | Add parentheses. | Swift |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
let vec=vec![8,2,95]; let head=&vec[0]; vec.push(47); | let mut vec=vec![8,2,95]; let head=vec[0]; vec.push(47); | Copy instead of reference. | Rust |
SELECT * FROM products WHRE email=22; | SELECT * FROM products WHERE email=22; | Fix WHERE. | SQL |
match val {{ 1 => {{}} }} | match val {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
let num = 48; let num = 75; | let num = 48; num = 75; | Duplicate declaration. | JavaScript |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
val b = 'test' | val b = "test" | Double quotes. | Kotlin |
while item > 16
item -= 1 | while item > 16:
item -= 1 | Colon missing after while. | Python |
print 'output' | print 'output'; | Add semicolon. | Perl |
'63' + 48 | 63 + 48 | Avoid string coercion. | JavaScript |
let index = 'data' | let index = "data" | Double quotes. | Swift |
<entry name='data'/> | <entry name="data"/> | Double quotes. | XML |
["hello", 55] | ["hello", 55] | Correct. | JSON |
if item > 25
print('value') | if item > 25:
print('value') | Colon missing after if. | Python |
b == '34' | b === 34 | Use strict equality. | JavaScript |
for (int i=0; i<88; i++) {{}} | for (int i=0; i<88; i++) {{}} | Correct. | Java |
const c; | const c = 6; | Initialize const. | JavaScript |
const user:Person = {{name:'world'}}; | const user:Person = {{name:'world', age:61}}; | Add missing property. | TypeScript |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
if [ $data = 67 ]; then | if [ "$data" = 67 ]; then | Quote variable. | Shell |
<center>output</center> | <div style='text-align:center;'>output</div> | Use CSS. | HTML |
'result' + 89 | 'result' + 89.to_s | Convert int. | Ruby |
if temp = 12: | if temp == 12: | Use == for comparison. | Python |
[24, 53, 47 | [24, 53, 47] | Close bracket. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
fn render() -> i32 {{ 63 }} | fn render() -> i32 {{ 63 }} | Correct. | Rust |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
if (val = 44) {{}} | if (val == 44) {{}} | Use ==. | Java |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
arr[7] | if arr.indices.contains(7) {{ arr[7] }} | Check index. | Swift |
.Order {{ color: red; }} | .Order {{ color: red; }} | Correct. | CSS |
if c = 40 {{}} | if c == 40 {{}} | Use ==. | Swift |
var x int | var x int | Correct. | Go |
for i=1,15 do print(i) end | for i=1,15 do print(i) end | Correct. | Lua |
disp('hello') | disp('hello') | Correct. | MATLAB |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
for num in range(77)
print(num) | for num in range(77):
print(num) | Colon after for. | Python |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
if result = 23 | if result == 23 | Use ==. | MATLAB |
h1 {{ font-size:92px color:#333; }} | h1 {{ font-size:92px; color:#333; }} | Add semicolon. | CSS |
<person><name>info</name><name>86</name></person | <person><name>info</name><name>86</name></person> | Add closing >. | XML |
math.sqrt(40) | import math
math.sqrt(40) | Import module first. | Python |
let val = 62; val += 1; | let mut val = 62; val += 1; | Need mut to modify. | Rust |
INSERT INTO orders VALUES ('output',40) | INSERT INTO orders (id, email) VALUES ('output',40); | Specify columns. | SQL |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
function handle() {{
return
{{key:'world'}}
}} | function handle() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
{{"status":"value",}} | {{"status":"value"}} | Remove trailing comma. | JSON |
$list[67] = 5; | if (isset($list[67])) $list[67] = 5; | Check existence. | PHP |
<br></br> | <br> | Self-closing. | HTML |
data[34] | if data.indices.contains(34) {{ data[34] }} | Check index. | Swift |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let msg = String::from("message"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("message"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
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