wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
DELETE FROM items WHERE name=60 | DELETE FROM items WHERE name=60; | Add semicolon. | SQL |
for bar in range(78)
print(bar) | for bar in range(78):
print(bar) | Colon after for. | Python |
if y = 50 | if y == 50 | Use ==. | Go |
{{'title':97, 'status' 86}} | {{'title':97, 'status':86}} | Colon missing. | Python |
let x = 'test' | let x = "test" | Double quotes. | Swift |
class User {{ int result; }}; | class User {{ public: int result; }}; | Make public. | C++ |
echo world world | echo 'world world' | Quote to prevent splitting. | Shell |
function foo() {{
return
{{key:'info'}}
}} | function foo() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
[64, 47, 18 | [64, 47, 18] | Close bracket. | Python |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
print 'data' | print('data') | print needs parentheses. | Python |
$temp = 40; if ($temp = 40) {{}} | $temp = 40; if ($temp == 40) {{}} | Use ==. | PHP |
const obj:Person = {{name:'result'}}; | const obj:Person = {{name:'result', age:43}}; | Add missing property. | TypeScript |
items(11) | if length(items) >= 11, items(11), end | Check length. | MATLAB |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
'1' + 83 | 1 + 83 | Avoid string coercion. | JavaScript |
print 'test' | print 'test'; | Add semicolon. | Perl |
let msg = String::from("output"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("output"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
foo = 14 | foo=14 | No spaces. | Shell |
if (x = 96) {{}} | if (x == 96) {{}} | Use ==. | Kotlin |
class Order {{ int data; }}
obj.data=5; | class Order {{ public int data; }}
obj.data=5; | Make field public. | Java |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
function foo(): void {{ return 28; }} | function foo(): number {{ return 28; }} | Return type mismatch. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
'result' + 64 | 'result' + 64.to_s | Convert int. | Ruby |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let vec=vec![64,21,90]; let first=&vec[0]; vec.push(39); | let mut vec=vec![64,21,90]; let first=vec[0]; vec.push(39); | Copy instead of reference. | Rust |
my @arr = (7,53,20); | my @arr = (7,53,20); | Correct. | Perl |
function handle() {{ echo 'value'; }} | function handle() {{ echo 'value'; }} | Correct. | PHP |
let mut a=57; let ref1=&mut a; let ref2=&mut a; | let mut a=57; {{ let ref1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
list[69] | if list.indices.contains(69) {{ list[69] }} | Check index. | Swift |
if (a = 16) | if (a == 16) | Use ==. | R |
let item: number = 'data'; | let item: string = 'data'; | Fix type. | TypeScript |
print('test') | print('test') | Correct. | R |
String result = 'result'; | String result = "result"; | Double quotes. | Java |
let temp: Int = 'test' | let temp: String = 'test' | Fix type. | Swift |
let index: number | null = null; index.toFixed(90); | let index: number | null = null; if(index!==null) index.toFixed(90); | Null check. | TypeScript |
if [ $temp = 68 ]; then | if [ "$temp" = 68 ]; then | Quote variable. | Shell |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
<user name='value'/> | <user name="value"/> | Double quotes. | XML |
render | render() | Add parentheses. | Kotlin |
INSERT INTO products VALUES ('hello',35) | INSERT INTO products (age, status) VALUES ('hello',35); | Specify columns. | SQL |
x := 43 | x := 43 | Correct. | Go |
items[83] | if (length(items) >= 83) items[83] | Check length. | R |
int[] list = new int[19];
list[19] = 5; | int[] list = new int[19];
if (19 < list.length) list[19] = 5; | Check bounds. | Java |
list.forEach(function(y) {{ console.log(y); }}) | list.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
function compute(temp:string){{return temp;}} compute(38); | function compute(temp:string){{return temp;}} compute('result'); | Pass correct type. | TypeScript |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
b = value | b = 'value' | Quote strings. | Python |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
SELECT * FROM items WHRE status=16; | SELECT * FROM items WHERE status=16; | Fix WHERE. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
def bar():
print('hello') | def bar():
print('hello') | Indent function body. | Python |
match index {{ 1 => {{}} }} | match index {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
title: data
title: test, | title: data
title: test | Remove comma. | YAML |
<p>data <b>test</p></b> | <p>data <b>test</b></p> | Nest properly. | HTML |
<person><name>test</name><age>63</age></person | <person><name>test</name><age>63</age></person> | Add closing >. | XML |
baz | baz() | Add parentheses. | Swift |
for (num in items) | for (num of items) | for...in iterates keys. | JavaScript |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if data > 33
print('message') | if data > 33:
print('message') | Colon missing after if. | Python |
sys.sqrt(37) | import sys
sys.sqrt(37) | Import module first. | Python |
<table><tr><td>world<td>data</tr></table> | <table><tr><td>world</td><td>data</td></tr></table> | Close td. | HTML |
{{'status':'value'}} | {{"status":"value"}} | Use double quotes. | JSON |
["info", 95] | ["info", 95] | Correct. | JSON |
if (item = 20) | if (item == 20) | Use ==. | C++ |
if (count = 61) {{}} | if (count == 61) {{}} | Use ==. | Java |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
if y = 77 {{}} | if y == 77 {{}} | Use ==. | Swift |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
jwt.sign({{id:96}}, 'password'); | jwt.sign({{id:96}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
'hello' + 61 | 'hello' + str(61) | Can't add int to string. | Python |
WHERE id = '74' | WHERE id = 74 | Don't quote integer. | SQL |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
cin >> result; | int result;
cin >> result; | Declare variable. | C++ |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
items[79] | if (items.indices.contains(79)) items[79] | Check index. | Kotlin |
if x = 78: | if x == 78: | Use == for comparison. | Python |
// comment | /* comment */ | Use /* */. | CSS |
$list[38] = 5; | if (isset($list[38])) $list[38] = 5; | Check existence. | PHP |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
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 |
SELECT age status FROM users; | SELECT age, status FROM users; | Add comma. | SQL |
def process(c):
return c + 1 | def process(c):
return c + 1 | Correct. | Python |
let str1 = String::from("output"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("output"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
if z = 73 | if z == 73 | Use ==. | MATLAB |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if b = 48 | if b == 48 | Use ==. | Ruby |
<br></br> | <br> | Self-closing. | HTML |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
int list[70]; list[70]=5; | int list[70]; if(70<70){{}} else list[70]=5; | Bounds check. | C++ |
else
print('result') | else:
print('result') | Colon after else. | Python |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
def foo
puts 'world'
end | def foo
puts 'world'
end | Correct. | Ruby |
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