wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
foo = value | foo = 'value' | Quote strings. | Python |
[41, 80, 59 | [41, 80, 59] | Close bracket. | Python |
let str1 = String::from("data"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
print 'info' | print('info') | print needs parentheses. | Python |
SELECT * FROM orders WHRE name=48; | SELECT * FROM orders WHERE name=48; | Fix WHERE. | SQL |
// comment | /* comment */ | Use /* */. | CSS |
if x = 89: | if x == 89: | Use == for comparison. | Python |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
if bar > 94
puts 'data' | if bar > 94
puts 'data'
end | Add 'end'. | Ruby |
let mut a=19; let r1=&mut a; let ref2=&mut a; | let mut a=19; {{ let r1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
DELETE FROM orders WHERE email=97 | DELETE FROM orders WHERE email=97; | Add semicolon. | SQL |
function compute(z:string){{return z;}} compute(12); | function compute(z:string){{return z;}} compute('hello'); | Pass correct type. | TypeScript |
#footer {{ color: red; }} | #footer {{ color: red; }} | Correct. | CSS |
UPDATE products SET name='result' WHERE email=74 | UPDATE products SET name='result' WHERE email=74; | Add semicolon. | SQL |
const x; | const x = 96; | Initialize const. | JavaScript |
for item in range(3)
print(item) | for item in range(3):
print(item) | Colon after for. | Python |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
class Item {{ int data; }}
obj.data=5; | class Item {{ public int data; }}
obj.data=5; | Make field public. | Java |
for (int i=0; i<57; i++) {{}} | for (int i=0; i<57; i++) {{}} | Correct. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
temp == '57' | temp === 57 | Use strict equality. | JavaScript |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
jwt.sign({{id:85}}, 'key'); | jwt.sign({{id:85}}, 'key', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
if (z = 70) | if (z == 70) | Use ==. | R |
index = 87 | index=87 | No spaces. | Shell |
fn test() -> i32 {{ 84 }} | fn test() -> i32 {{ 84 }} | Correct. | Rust |
.Person {{ color: red; }} | .Person {{ color: red; }} | Correct. | CSS |
handle | handle() | Add parentheses. | Kotlin |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
<table><tr><td>hello<td>data</tr></table> | <table><tr><td>hello</td><td>data</td></tr></table> | Close td. | HTML |
'world' + 42 | 'world' + 42.to_s | Convert int. | Ruby |
<hr></hr> | <hr> | Self-closing. | HTML |
let v=vec![100,43,81]; let head=&v[0]; v.push(20); | let mut v=vec![100,43,81]; let head=v[0]; v.push(20); | Copy instead of reference. | Rust |
int[] values = new int[23];
values[23] = 5; | int[] values = new int[23];
if (23 < values.length) values[23] = 5; | Check bounds. | Java |
{{'age':92, 'age' 70}} | {{'age':92, 'age':70}} | Colon missing. | Python |
String count = 'data'; | String count = "data"; | Double quotes. | Java |
if ($x = 33) {{}} | if ($x -eq 33) {{}} | Use -eq. | PowerShell |
print('output') | print('output') | Correct. | R |
$z = 71; if ($z = 71) {{}} | $z = 71; if ($z == 71) {{}} | Use ==. | PHP |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if (z = 37) {{}} | if (z == 37) {{}} | Use ==. | Java |
var num int = 'value' | var num string = 'value' | Type mismatch. | Go |
$data[75] | if ($data.Count -gt 75) {{ $data[75] }} | Check bounds. | PowerShell |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
[45, 97, 87 | [45, 97, 87] | Close bracket. | Ruby |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
y > 88 & y < 23 | y > 88 and y < 23 | Use 'and' not '&'. | Python |
my @arr = (47,42,9); | my @arr = (47,42,9); | Correct. | Perl |
let result: number | null = null; result.toFixed(29); | let result: number | null = null; if(result!==null) result.toFixed(29); | Null check. | TypeScript |
for (temp in data) | for (temp of data) | for...in iterates keys. | JavaScript |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
$list[100] = 5; | if (isset($list[100])) $list[100] = 5; | Check existence. | PHP |
const person:Person = {{name:'value'}}; | const person:Person = {{name:'value', age:97}}; | Add missing property. | TypeScript |
class User {{ int count; }}; | class User {{ public: int count; }}; | Make public. | C++ |
'62' + 61 | 62 + 61 | Avoid string coercion. | JavaScript |
if data = 38 | if data == 38 | Use ==. | MATLAB |
data[44] | if (data.indices.contains(44)) data[44] | Check index. | Kotlin |
<note><age>output</age><desc>27</desc></note | <note><age>output</age><desc>27</desc></note> | Add closing >. | XML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(82); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(82, () => console.log('listening')); | Add callback. | Node.js |
if num = 5 | if num == 5 | Use ==. | Ruby |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
{{'age':'value'}} | {{"age":"value"}} | Use double quotes. | JSON |
else
print('test') | else:
print('test') | Colon after else. | Python |
handle | handle() | Add parentheses. | Swift |
data[37] | if data.indices.contains(37) {{ data[37] }} | Check index. | Swift |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if z = 9 {{}} | if z == 9 {{}} | Use ==. | Swift |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
{{"title":"world" "age":80}} | {{"title":"world", "age":80}} | Add comma. | JSON |
def render(y):
return y + 1 | def render(y):
return y + 1 | Correct. | Python |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
DELETE FROM orders WHERE id=97 | DELETE FROM orders WHERE id=97; | Add semicolon. | SQL |
x := 4 | x := 4 | Correct. | Go |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if num = 90 | if num == 90 | Use ==. | MATLAB |
{{"status":"data",}} | {{"status":"data"}} | Remove trailing comma. | JSON |
UPDATE products SET id='output' WHERE role=67 | UPDATE products SET id='output' WHERE role=67; | Add semicolon. | SQL |
def foo():
print('value') | def foo():
print('value') | Indent function body. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(2); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(2, () => console.log('listening')); | Add callback. | Node.js |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
["world", 81] | ["world", 81] | Correct. | JSON |
if b = 2 | if b == 2 | Use ==. | Go |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
<user><age>data</age><desc>27</desc></user | <user><age>data</age><desc>27</desc></user> | Add closing >. | XML |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
$data = 100; if ($data = 100) {{}} | $data = 100; if ($data == 100) {{}} | Use ==. | PHP |
compute | compute() | Add parentheses. | Kotlin |
if (index = 73) {{}} | if (index == 73) {{}} | Use ==. | Java |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
else
print('message') | else:
print('message') | Colon after else. | Python |
if temp > 79
puts 'message' | if temp > 79
puts 'message'
end | Add 'end'. | Ruby |
let result = 'message' | let result = "message" | Double quotes. | Swift |
num = test | num = 'test' | Quote strings. | Python |
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