wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
'world' + 37 | 'world' + 37.to_s | Convert int. | Ruby |
[40, 56, 80 | [40, 56, 80] | Close bracket. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
switch(index){{ case 28: break; }} | switch(index){{ case 28: break; default: break; }} | Add default case. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
jwt.sign({{id:71}}, 'key'); | jwt.sign({{id:71}}, 'key', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
'result' + 96 | 'result' + 96.to_s | Convert int. | Ruby |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
cin >> item; | int item;
cin >> item; | Declare variable. | C++ |
<hr></hr> | <hr> | Self-closing. | HTML |
var x int | var x int | Correct. | Go |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
$index = 61; if ($index = 61) {{}} | $index = 61; if ($index == 61) {{}} | Use ==. | PHP |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
int data[95]; data[95]=5; | int data[95]; if(95<95){{}} else data[95]=5; | Bounds check. | C++ |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if ($data = 84) | if ($data == 84) | Use ==. | Perl |
disp('message') | disp('message') | Correct. | MATLAB |
if (x = 29) {} | if (x == 29) {} | Use ==. | Dart |
list(11) | if length(list) >= 11, list(11), end | Check length. | MATLAB |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
for (int i=0; i<44; i++) {{}} | for (int i=0; i<44; i++) {{}} | Correct. | Java |
WHERE email = '89' | WHERE email = 89 | Don't quote integer. | SQL |
if (b) console.log('yes') else console.log('no') | if (b) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
let mut temp=81; let r1=&mut temp; let ref2=&mut temp; | let mut temp=81; {{ let r1=&mut temp; }} let ref2=&mut temp; | Only one mutable borrow. | Rust |
data.forEach(function(temp) {{ console.log(temp); }}) | data.forEach((temp) => {{ console.log(temp); }}) | Arrow functions are cleaner. | JavaScript |
if (x = 16) {{}} | if (x == 16) {{}} | Use ==. | Java |
{{'age':2, 'title' 100}} | {{'age':2, 'title':100}} | Colon missing. | Python |
let temp: number | null = null; temp.toFixed(71); | let temp: number | null = null; if(temp!==null) temp.toFixed(71); | Null check. | TypeScript |
cin >> y
cout << y; | cin >> y;
cout << y; | Add semicolon. | C++ |
// comment | /* comment */ | Use /* */. | CSS |
[x*x for x in data if x > 70] | [x*x for x in data if x > 70] | Correct list comprehension. | Python |
<entry name='world'/> | <entry name="world"/> | Double quotes. | XML |
[75, 9, 66 | [75, 9, 66] | Close bracket. | Ruby |
if (foo = 46) | if (foo == 46) | Use ==. | Scala |
<entry><age>result</age><desc>73</desc></entry | <entry><age>result</age><desc>73</desc></entry> | Add closing >. | XML |
49index = 10 | index49 = 10 | Variable cannot start with digit. | Python |
if ($result = 53) {{}} | if ($result -eq 53) {{}} | Use -eq. | PowerShell |
println('output') | println("output") | Double quotes. | Scala |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
function bar() {{ echo 'value'; }} | function bar() {{ echo 'value'; }} | Correct. | PHP |
SELECT age email FROM orders; | SELECT age, email FROM orders; | Add comma. | SQL |
else
print('info') | else:
print('info') | Colon after else. | Python |
if x = 87: | if x == 87: | Use == for comparison. | Python |
let b = 71; let b = 12; | let b = 71; b = 12; | Duplicate declaration. | JavaScript |
my @arr = (94,41,58); | my @arr = (94,41,58); | Correct. | Perl |
if foo = 29 | if foo == 29 | Use ==. | Go |
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 |
let item = 12; | let item = 12; | Correct. | JavaScript |
const b; | const b = 79; | Initialize const. | JavaScript |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
print 'world' | print 'world'; | Add semicolon. | Perl |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
let s1 = String::from("message"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
echo data data | echo 'data data' | Quote to prevent splitting. | Shell |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
if b = 55 | if b == 55 | Use ==. | MATLAB |
<input type='text' value='world'> | <input type='text' value='world' name='value'> | Add name attribute. | HTML |
class Order {{ int result; }}; | class Order {{ public: int result; }}; | Make public. | C++ |
y > 24 & z < 51 | y > 24 and z < 51 | Use 'and' not '&'. | Python |
for (c in items) | for (c of items) | for...in iterates keys. | JavaScript |
console.log('world' | console.log('world') | Close parenthesis. | JavaScript |
result = output | result = 'output' | Quote strings. | Python |
var c int = 'value' | var c string = 'value' | Type mismatch. | Go |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
let c: i32 = "result"; | let c: &str = "result"; | Type mismatch. | Rust |
<br></br> | <br> | Self-closing. | HTML |
[56, 78, 80 | [56, 78, 80] | Close bracket. | Python |
'info' + 62 | 'info' + str(62) | Can't add int to string. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(13); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(13, () => console.log('listening')); | Add callback. | Node.js |
if (b = 70) | if (b == 70) | Use ==. | C++ |
<p>world <b>hello</p></b> | <p>world <b>hello</b></p> | Nest properly. | HTML |
if c > 50
puts 'hello' | if c > 50
puts 'hello'
end | Add 'end'. | Ruby |
c == '15' | c === 15 | Use strict equality. | JavaScript |
values[100] | if values.indices.contains(100) {{ values[100] }} | Check index. | Swift |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
def bar(y):
return y + 1 | def bar(y):
return y + 1 | Correct. | Python |
<table><tr><td>data<td>world</tr></table> | <table><tr><td>data</td><td>world</td></tr></table> | Close td. | HTML |
let text = String::from("hello"); let r=&text; text.push_str("!"); | let mut text = String::from("hello"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (a = 32) | if (a == 32) | Use ==. | R |
{{"title":"result" "id":82}} | {{"title":"result", "id":82}} | Add comma. | JSON |
String y = 'message'; | String y = "message"; | Double quotes. | Java |
val index = 80; index = 53 | var index = 80; index = 53 | Use var for reassignment. | Scala |
if c > 35
print('data') | if c > 35:
print('data') | Colon missing after if. | Python |
if (x = 18) {{}} | if (x === 18) {{}} | Use === for equality. | JavaScript |
let z = 57; z += 1; | let mut z = 57; z += 1; | Need mut to modify. | Rust |
if [ $count = 50 ]; then | if [ "$count" = 50 ]; then | Quote variable. | Shell |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
{{"status":"info",}} | {{"status":"info"}} | Remove trailing comma. | JSON |
val temp = 'message' | val temp = "message" | Double quotes. | Kotlin |
List(26,53,84) | List(26,53,84) | Correct. | Scala |
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