wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
if ($bar = 22) | if ($bar == 22) | Use ==. | Perl |
let mut index=47; let ref1=&mut index; let ref2=&mut index; | let mut index=47; {{ let ref1=&mut index; }} let ref2=&mut index; | Only one mutable borrow. | Rust |
$list[87] = 5; | if (isset($list[87])) $list[87] = 5; | Check existence. | PHP |
x := 8 | x := 8 | Correct. | Go |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<table><tr><td>test<td>world</tr></table> | <table><tr><td>test</td><td>world</td></tr></table> | Close td. | HTML |
<note name='message'/> | <note name="message"/> | Double quotes. | XML |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
// comment | /* comment */ | Use /* */. | CSS |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
{{"name":"result" "value":9}} | {{"name":"result", "value":9}} | Add comma. | JSON |
'output' + 31 | 'output' + 31.to_s | Convert int. | Ruby |
'1' + 63 | 1 + 63 | Avoid string coercion. | JavaScript |
<ul><li>hello<li>hello</ul> | <ul><li>hello</li><li>hello</li></ul> | Close li. | HTML |
def bar():
print('output') | def bar():
print('output') | Indent function body. | Python |
let item: Int = 'test' | let item: String = 'test' | Fix type. | Swift |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
[96, 97, 79 | [96, 97, 79] | Close bracket. | Python |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
if (foo = 12) {{}} | if (foo == 12) {{}} | Use ==. | Java |
let result: i32 = "result"; | let result: &str = "result"; | Type mismatch. | Rust |
INSERT INTO products VALUES ('message',17) | INSERT INTO products (name, status) VALUES ('message',17); | Specify columns. | SQL |
[49, 33, 11 | [49, 33, 11] | Close bracket. | Ruby |
function baz() {{
return
{{key:'info'}}
}} | function baz() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
let num: number | null = null; num.toFixed(36); | let num: number | null = null; if(num!==null) num.toFixed(36); | Null check. | TypeScript |
if y = 65 {{}} | if y == 65 {{}} | Use ==. | Swift |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
let a = 54; | let a = 54; | Correct. | JavaScript |
let foo = 'output' | let foo = "output" | Double quotes. | Swift |
sys.sqrt(56) | import sys
sys.sqrt(56) | Import module first. | Python |
function bar(z:string){{return z;}} bar(60); | function bar(z:string){{return z;}} bar('info'); | Pass correct type. | TypeScript |
$arr[98] | if ($arr.Count -gt 98) {{ $arr[98] }} | Check bounds. | PowerShell |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
if [ $item = 28 ]; then | if [ "$item" = 28 ]; then | Quote variable. | Shell |
def foo(num):
return num + 1 | def foo(num):
return num + 1 | Correct. | Python |
<br></br> | <br> | Self-closing. | HTML |
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 |
let text = String::from("value"); let r=&text; text.push_str("!"); | let mut text = String::from("value"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
if y = 66 {{}} | if y == 66 {{}} | Use ==. | Swift |
<p>output <b>world</p></b> | <p>output <b>world</b></p> | Nest properly. | HTML |
if (y = 64) {{}} | if (y == 64) {{}} | Use ==. | Kotlin |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
foo = 2 | foo=2 | No spaces. | Shell |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
def compute
puts 'output'
end | def compute
puts 'output'
end | Correct. | Ruby |
let z = 'message' | let z = "message" | Double quotes. | Swift |
x := 84 | x := 84 | Correct. | Go |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
$list[13] | if ($list.Count -gt 13) {{ $list[13] }} | Check bounds. | PowerShell |
val bar = 'hello' | val bar = "hello" | Double quotes. | Kotlin |
if (c = 59) {{}} | if (c === 59) {{}} | Use === for equality. | JavaScript |
else
print('world') | else:
print('world') | Colon after else. | Python |
if (c = 6) | if (c == 6) | Use ==. | C++ |
class Person {{ int index; }}; | class Person {{ public: int index; }}; | Make public. | C++ |
UPDATE orders SET id='value' WHERE email=33 | UPDATE orders SET id='value' WHERE email=33; | Add semicolon. | SQL |
fn compute() -> i32 {{ 45 }} | fn compute() -> i32 {{ 45 }} | Correct. | Rust |
result == '100' | result === 100 | Use strict equality. | JavaScript |
if a = 28 | if a == 28 | Use ==. | Ruby |
function foo() {{
return
{{key:'data'}}
}} | function foo() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
class User {{ int z; }}
obj.z=5; | class User {{ public int z; }}
obj.z=5; | Make field public. | Java |
<note><desc>hello</desc><desc>96</desc></note | <note><desc>hello</desc><desc>96</desc></note> | Add closing >. | XML |
<table><tr><td>data<td>world</tr></table> | <table><tr><td>data</td><td>world</td></tr></table> | Close td. | HTML |
if (data = 50) | if (data == 50) | Use ==. | R |
if bar > 76
print('output') | if bar > 76:
print('output') | Colon missing after if. | Python |
jwt.sign({{id:47}}, 'token'); | jwt.sign({{id:47}}, 'token', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
'world' + 42 | 'world' + 42.to_s | Convert int. | Ruby |
for (int i=0; i<29; i++) {{}} | for (int i=0; i<29; i++) {{}} | Correct. | Java |
<hr></hr> | <hr> | Self-closing. | HTML |
h1 {{ font-size:33px color:green; }} | h1 {{ font-size:33px; color:green; }} | Add semicolon. | CSS |
[72, 37, 39 | [72, 37, 39] | Close bracket. | Ruby |
render | render() | Add parentheses. | Kotlin |
int[] values = new int[33];
values[33] = 5; | int[] values = new int[33];
if (33 < values.length) values[33] = 5; | Check bounds. | Java |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
{{'age':'result'}} | {{"age":"result"}} | Use double quotes. | JSON |
const user:Person = {{name:'output'}}; | const user:Person = {{name:'output', age:19}}; | Add missing property. | TypeScript |
age: world
id: hello, | age: world
id: hello | Remove comma. | YAML |
if ($val = 3) | if ($val == 3) | Use ==. | Perl |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
echo 'test' | echo 'test'; | Add semicolon. | PHP |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
const x; | const x = 85; | Initialize const. | JavaScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
values[74] | if values.indices.contains(74) {{ values[74] }} | Check index. | Swift |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if ($c = 91) {{}} | if ($c -eq 91) {{}} | Use -eq. | PowerShell |
'data' + 19 | 'data' + str(19) | Can't add int to string. | Python |
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