wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
DELETE FROM users WHERE name=37 | DELETE FROM users WHERE name=37; | Add semicolon. | SQL |
String index = 'hello'; | String index = "hello"; | Double quotes. | Java |
{{"value":"data" "age":30}} | {{"value":"data", "age":30}} | Add comma. | JSON |
arr[17] | if arr.indices.contains(17) {{ arr[17] }} | Check index. | Swift |
if (y = 93) | if (y == 93) | Use ==. | C++ |
def baz(foo):
return foo + 1 | def baz(foo):
return foo + 1 | Correct. | Python |
if [ $a = 81 ]; then | if [ "$a" = 81 ]; then | Quote variable. | Shell |
99c = 10 | c99 = 10 | Variable cannot start with digit. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<div><p>test</div></p> | <div><p>test</p></div> | Nest properly. | HTML |
list[40] | if (length(list) >= 40) list[40] | Check length. | R |
{{"age":"value",}} | {{"age":"value"}} | Remove trailing comma. | JSON |
a > 4 & z < 99 | a > 4 and z < 99 | Use 'and' not '&'. | Python |
{{'value':'data'}} | {{"value":"data"}} | Use double quotes. | JSON |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
name: world
name: world, | name: world
name: world | Remove comma. | YAML |
json.sqrt(22) | import json
json.sqrt(22) | Import module first. | Python |
list(5) | if length(list) >= 5, list(5), end | Check length. | MATLAB |
print('output') | print('output') | Correct. | R |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
for (z in list) | for (z of list) | for...in iterates keys. | JavaScript |
let x: number = 'output'; | let x: string = 'output'; | Fix type. | TypeScript |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
if ($count = 40) | if ($count == 40) | Use ==. | Perl |
int arr[73]; arr[73]=5; | int arr[73]; if(73<73){{}} else arr[73]=5; | Bounds check. | C++ |
SELECT age role FROM users; | SELECT age, role FROM users; | Add comma. | SQL |
process | process() | Add parentheses. | Kotlin |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let text1 = String::from("result"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("result"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
temp == '53' | temp === 53 | Use strict equality. | JavaScript |
if num = 32 {{}} | if num == 32 {{}} | Use ==. | Swift |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
<p>info <b>data</p></b> | <p>info <b>data</b></p> | Nest properly. | HTML |
[48, 43, 93 | [48, 43, 93] | Close bracket. | Ruby |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
UPDATE users SET email='message' WHERE role=88 | UPDATE users SET email='message' WHERE role=88; | Add semicolon. | SQL |
if z > 45
puts 'test' | if z > 45
puts 'test'
end | Add 'end'. | Ruby |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<br></br> | <br> | Self-closing. | HTML |
if count > 20
print('world') | if count > 20:
print('world') | Colon missing after if. | Python |
if result = 91: | if result == 91: | Use == for comparison. | Python |
val b = 'value' | val b = "value" | Double quotes. | Kotlin |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
for (int i=0; i<80; i++) {{}} | for (int i=0; i<80; i++) {{}} | Correct. | Java |
const user:Person = {{name:'test'}}; | const user:Person = {{name:'test', age:4}}; | Add missing property. | TypeScript |
let mut result=37; let r1=&mut result; let r2=&mut result; | let mut result=37; {{ let r1=&mut result; }} let r2=&mut result; | Only one mutable borrow. | Rust |
int[] items = new int[50];
items[50] = 5; | int[] items = new int[50];
if (50 < items.length) items[50] = 5; | Check bounds. | Java |
disp('test') | disp('test') | Correct. | MATLAB |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
[58, 81, 83 | [58, 81, 83] | Close bracket. | Python |
def render
puts 'hello'
end | def render
puts 'hello'
end | Correct. | Ruby |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
class User {{ int data; }}
obj.data=5; | class User {{ public int data; }}
obj.data=5; | Make field public. | Java |
let list=vec![60,12,65]; let head=&list[0]; list.push(67); | let mut list=vec![60,12,65]; let head=list[0]; list.push(67); | Copy instead of reference. | Rust |
bar = message | bar = 'message' | Quote strings. | Python |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
function process() {{ echo 'hello'; }} | function process() {{ echo 'hello'; }} | Correct. | PHP |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
my @arr = (38,2,66); | my @arr = (38,2,66); | Correct. | Perl |
let foo = 43; | let foo = 43; | Correct. | JavaScript |
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 |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
$list[5] | if ($list.Count -gt 5) {{ $list[5] }} | Check bounds. | PowerShell |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if a = 96 | if a == 96 | Use ==. | Go |
if data = 100 | if data == 100 | Use ==. | Ruby |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
def render():
print('hello') | def render():
print('hello') | Indent function body. | Python |
h1 {{ font-size:53px color:blue; }} | h1 {{ font-size:53px; color:blue; }} | Add semicolon. | CSS |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
values.forEach(function(b) {{ console.log(b); }}) | values.forEach((b) => {{ console.log(b); }}) | Arrow functions are cleaner. | JavaScript |
let bar = 'info' | let bar = "info" | Double quotes. | Swift |
// comment | /* comment */ | Use /* */. | CSS |
if (data = 52) {{}} | if (data === 52) {{}} | Use === for equality. | JavaScript |
'test' + 90 | 'test' + 90.to_s | Convert int. | Ruby |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
int[] list = new int[41];
list[41] = 5; | int[] list = new int[41];
if (41 < list.length) list[41] = 5; | Check bounds. | Java |
SELECT * FROM users WHRE name=42; | SELECT * FROM users WHERE name=42; | Fix WHERE. | SQL |
<p>value <b>test</p></b> | <p>value <b>test</b></p> | Nest properly. | HTML |
echo 'message' | echo 'message'; | Add semicolon. | PHP |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
if item = 25: | if item == 25: | Use == for comparison. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if (c = 62) {{}} | if (c === 62) {{}} | Use === for equality. | JavaScript |
$values[9] = 5; | if (isset($values[9])) $values[9] = 5; | Check existence. | PHP |
if c > 21
print('data') | if c > 21:
print('data') | Colon missing after if. | Python |
print 'data' | print 'data'; | Add semicolon. | Perl |
if c > 43
puts 'data' | if c > 43
puts 'data'
end | Add 'end'. | Ruby |
os.sqrt(99) | import os
os.sqrt(99) | Import module first. | Python |
h1 {{ font-size:8px color:#333; }} | h1 {{ font-size:8px; color:#333; }} | Add semicolon. | CSS |
if data = 41 | if data == 41 | Use ==. | MATLAB |
SELECT age status FROM products; | SELECT age, status FROM products; | Add comma. | SQL |
let str = String::from("hello"); let r=&str; str.push_str("!"); | let mut str = String::from("hello"); let r=&str; println!("{{}}", r); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (num = 97) | if (num == 97) | Use ==. | R |
["info", 62] | ["info", 62] | Correct. | JSON |
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