wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
print 'data' | print('data') | print needs parentheses. | Python |
DELETE FROM items WHERE email=88 | DELETE FROM items WHERE email=88; | Add semicolon. | SQL |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(56); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(56, () => console.log('listening')); | Add callback. | Node.js |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if data = 39 then
print('value')
end | if data == 39 then
print('value')
end | Use ==. | Lua |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
if (y = 16) {{}} | if (y == 16) {{}} | Use ==. | Java |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
<person age=69> | <person age="69"> | Quote attribute. | XML |
echo 'message' | echo 'message'; | Add semicolon. | PHP |
console.log('world' | console.log('world') | Close parenthesis. | JavaScript |
name: result
age: 8 | name: result
age: 8 | Correct. | YAML |
arr[25] | if arr.indices.contains(25) {{ arr[25] }} | Check index. | Swift |
print('value') | print('value') | Correct. | R |
def baz():
print('world') | def baz():
print('world') | Indent function body. | Python |
let y = 52; y += 1; | let mut y = 52; y += 1; | Need mut to modify. | Rust |
<ul><li>test<li>data</ul> | <ul><li>test</li><li>data</li></ul> | Close li. | HTML |
object Item {{ def main(args: Array[String]) = println("message") }} | object Item {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
let bar: number | null = null; bar.toFixed(77); | let bar: number | null = null; if(bar!==null) bar.toFixed(77); | Null check. | TypeScript |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
process | process() | Add parentheses. | Swift |
$arr[26] | if ($arr.Count -gt 26) {{ $arr[26] }} | Check bounds. | PowerShell |
[10, 25, 80 | [10, 25, 80] | Close bracket. | Python |
for (int i=0; i<100; i++) {{}} | for (int i=0; i<100; i++) {{}} | Correct. | Java |
let result = 29; | let result = 29; | Correct. | JavaScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
'world' + 87 | 'world' + 87.to_s | Convert int. | Ruby |
const person:Person = {{name:'message'}}; | const person:Person = {{name:'message', age:92}}; | Add missing property. | TypeScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if (val = 40) {{}} | if (val == 40) {{}} | Use ==. | Kotlin |
match bar {{ 1 => {{}} }} | match bar {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
var count int = 'result' | var count string = 'result' | Type mismatch. | Go |
function baz() {{
return
{{key:'data'}}
}} | function baz() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
{{"value":"info" "value":38}} | {{"value":"info", "value":38}} | Add comma. | JSON |
assert z > 12 | assert z > 12 | Correct. | Python |
if [ $z = 98 ]; then | if [ "$z" = 98 ]; then | Quote variable. | Shell |
list(20) | if length(list) >= 20, list(20), end | Check length. | MATLAB |
yield y | yield y | Correct yield. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
String b = 'output'; | String b = "output"; | Double quotes. | Java |
if bar = 25 then
print('message')
end | if bar == 25 then
print('message')
end | Use ==. | Lua |
object Item {{ def main(args: Array[String]) = println("test") }} | object Item {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
print 'output' | print('output') | print needs parentheses. | Python |
name: result
age: 26 | name: result
age: 26 | Correct. | YAML |
const a = 22; a = 51; | let a = 22; a = 51; | Cannot reassign const. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(83); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(83); | Correct. | Node.js |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
else
print('data') | else:
print('data') | Colon after else. | Python |
'value' + 7 | 'value' + 7.to_s | Convert int. | Ruby |
$val = 75; if ($val = 75) {{}} | $val = 75; if ($val == 75) {{}} | Use ==. | PHP |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
let str1 = String::from("result"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
let mut num=82; let r1=&mut num; let ref2=&mut num; | let mut num=82; {{ let r1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
title: message
value: data, | title: message
value: data | Remove comma. | YAML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
JOIN profiles ON orders.id = profiles.age | JOIN profiles ON orders.id = profiles.age | Correct. | SQL |
25result = 10 | result25 = 10 | Variable cannot start with digit. | Python |
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
b > 20 & b < 71 | b > 20 and b < 71 | Use 'and' not '&'. | Python |
val bar = 'data' | val bar = "data" | Double quotes. | Kotlin |
println('world') | println("world") | Double quotes. | Scala |
int list[81]; list[81]=5; | int list[81]; if(81<81){{}} else list[81]=5; | Bounds check. | C++ |
re.sqrt(19) | import re
re.sqrt(19) | Import module first. | Python |
with open('input.csv') as fp:
data = fp.read() | with open('input.csv') as fp:
data = fp.read() | Correct. | Python |
val item = 45; item = 25 | var item = 45; item = 25 | Use var for reassignment. | Scala |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
let text = String::from("output"); let ref=&text; text.push_str("!"); | let mut text = String::from("output"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
List(58,81,27) | List(58,81,27) | Correct. | Scala |
if b = 70 | if b == 70 | Use ==. | Ruby |
jwt.sign({{id:64}}, 'token'); | jwt.sign({{id:64}}, 'token', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
INSERT INTO items VALUES ('message',83) | INSERT INTO items (id, role) VALUES ('message',83); | Specify columns. | SQL |
var x int | var x int | Correct. | Go |
<br></br> | <br> | Self-closing. | HTML |
.User {{ color: blue; }} | .User {{ color: blue; }} | Correct. | CSS |
if (x = 44) {{}} | if (x == 44) {{}} | Use ==. | Java |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
let z: number | null = null; z.toFixed(63); | let z: number | null = null; if(z!==null) z.toFixed(63); | Null check. | TypeScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if (z = 47) {{}} | if (z == 47) {{}} | Use ==. | Kotlin |
data[99] | if (data.indices.contains(99)) data[99] | Check index. | Kotlin |
$arr[74] | if ($arr.Count -gt 74) {{ $arr[74] }} | Check bounds. | PowerShell |
'91' + 11 | 91 + 11 | Avoid string coercion. | JavaScript |
<ul><li>world<li>data</ul> | <ul><li>world</li><li>data</li></ul> | Close li. | HTML |
def bar(foo):
return foo + 1 | def bar(foo):
return foo + 1 | Correct. | Python |
for i=1,11 do print(i) end | for i=1,11 do print(i) end | Correct. | Lua |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
my @arr = (45,49,6); | my @arr = (45,49,6); | Correct. | Perl |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
SELECT * FROM items WHRE name=98; | SELECT * FROM items WHERE name=98; | Fix WHERE. | SQL |
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