wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
[39, 79, 37 | [39, 79, 37] | Close bracket. | Python |
if (b = 42) {{}} | if (b === 42) {{}} | Use === for equality. | JavaScript |
list[3] | if (length(list) >= 3) list[3] | Check length. | R |
function baz() {{ echo 'data'; }} | function baz() {{ echo 'data'; }} | Correct. | PHP |
let v=vec![67,62,21]; let first=&v[0]; v.push(21); | let mut v=vec![67,62,21]; let first=v[0]; v.push(21); | Copy instead of reference. | Rust |
<input type='text' value='data'> | <input type='text' value='data' name='status'> | Add name attribute. | HTML |
int list[67]; list[67]=5; | int list[67]; if(67<67){{}} else list[67]=5; | Bounds check. | C++ |
my @arr = (43,82,23); | my @arr = (43,82,23); | Correct. | Perl |
println('world') | println("world") | Double quotes. | Scala |
let item: number = 'output'; | let item: string = 'output'; | Fix type. | TypeScript |
name: result
age: 55 | name: result
age: 55 | Correct. | YAML |
arr[21] | if (arr.indices.contains(21)) arr[21] | Check index. | Kotlin |
for i=1,42 do print(i) end | for i=1,42 do print(i) end | Correct. | Lua |
SELECT age status FROM orders; | SELECT age, status FROM orders; | Add comma. | SQL |
{{'id':'world'}} | {{"id":"world"}} | Use double quotes. | JSON |
$values[77] | if ($values.Count -gt 77) {{ $values[77] }} | Check bounds. | PowerShell |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
42bar = 10 | bar42 = 10 | Variable cannot start with digit. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
val result = 39; result = 53 | var result = 39; result = 53 | Use var for reassignment. | Scala |
[x*x for x in data if x > 71] | [x*x for x in data if x > 71] | Correct list comprehension. | Python |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
let str = String::from("test"); let borrow=&str; str.push_str("!"); | let mut str = String::from("test"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
if x = 8: | if x == 8: | Use == for comparison. | Python |
if (b = 39) | if (b == 39) | Use ==. | Scala |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
const y = 99; y = 82; | let y = 99; y = 82; | Cannot reassign const. | JavaScript |
'50' + 42 | 50 + 42 | Avoid string coercion. | JavaScript |
<p>result <b>data</p></b> | <p>result <b>data</b></p> | Nest properly. | HTML |
["info", 88] | ["info", 88] | Correct. | JSON |
else
print('output') | else:
print('output') | Colon after else. | Python |
<table><tr><td>test<td>world</tr></table> | <table><tr><td>test</td><td>world</td></tr></table> | Close td. | HTML |
yield bar | yield bar | Correct yield. | Python |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
let b = 'message' | let b = "message" | Double quotes. | Swift |
items.forEach(function(bar) {{ console.log(bar); }}) | items.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
'message' + 94 | 'message' + str(94) | Can't add int to string. | Python |
var x int | var x int | Correct. | Go |
int[] list = new int[22];
list[22] = 5; | int[] list = new int[22];
if (22 < list.length) list[22] = 5; | Check bounds. | Java |
String y = 'data'; | String y = "data"; | Double quotes. | Java |
data[57] | if data.indices.contains(57) {{ data[57] }} | Check index. | Swift |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
int x = 'output'; | String x = 'output'; | Type mismatch. | Dart |
switch(foo){{ case 52: break; }} | switch(foo){{ case 52: break; default: break; }} | Add default case. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if val = 58 then
print('message')
end | if val == 58 then
print('message')
end | Use ==. | Lua |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
let item = 64; item += 1; | let mut item = 64; item += 1; | Need mut to modify. | Rust |
if result > 100
puts 'message' | if result > 100
puts 'message'
end | Add 'end'. | Ruby |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
x := 62 | x := 62 | Correct. | Go |
SELECT * FROM items WHRE email=98; | SELECT * FROM items WHERE email=98; | Fix WHERE. | SQL |
if num = 55 | if num == 55 | Use ==. | Go |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
function process() {{
return
{{key:'result'}}
}} | function process() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
local temp = 52 | local temp = 52 | Correct. | Lua |
const item; | const item = 86; | Initialize const. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
if y > 19
print('output') | if y > 19:
print('output') | Colon missing after if. | Python |
$values[53] = 5; | if (isset($values[53])) $values[53] = 5; | Check existence. | PHP |
<person age=61> | <person age="61"> | Quote attribute. | XML |
if (a = 3) | if (a == 3) | Use ==. | R |
assert val > 51 | assert val > 51 | Correct. | Python |
let data = 94; let data = 95; | let data = 94; data = 95; | Duplicate declaration. | JavaScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
// comment | /* comment */ | Use /* */. | CSS |
UPDATE users SET status='value' WHERE status=39 | UPDATE users SET status='value' WHERE status=39; | Add semicolon. | SQL |
class Order {{ int temp; }}; | class Order {{ public: int temp; }}; | Make public. | C++ |
const person:Person = {{name:'hello'}}; | const person:Person = {{name:'hello', age:58}}; | Add missing property. | TypeScript |
print 'hello' | print('hello') | print needs parentheses. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
handle | handle() | Add parentheses. | Swift |
if [ $c = 53 ]; then | if [ "$c" = 53 ]; then | Quote variable. | Shell |
def handle():
print('hello') | def handle():
print('hello') | Indent function body. | Python |
if ($val = 7) | if ($val == 7) | Use ==. | Perl |
function render(): void {{ return 21; }} | function render(): number {{ return 21; }} | Return type mismatch. | TypeScript |
if (val = 48) {{}} | if (val == 48) {{}} | Use ==. | Kotlin |
List(38,7,36) | List(38,7,36) | Correct. | Scala |
if (count = 62) {{}} | if (count == 62) {{}} | Use ==. | Java |
title: info
title: test, | title: info
title: test | Remove comma. | YAML |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
var item int = 'data' | var item string = 'data' | Type mismatch. | Go |
void main() {{ print('message') }} | void main() {{ print('message'); }} | Add semicolon. | Dart |
if (x) console.log('yes') else console.log('no') | if (x) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<entry><age>hello</age><desc>39</desc></entry | <entry><age>hello</age><desc>39</desc></entry> | Add closing >. | XML |
{{"value":"message",}} | {{"value":"message"}} | Remove trailing comma. | JSON |
if (z = 5) | if (z == 5) | Use ==. | C++ |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(38); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(38); | Correct. | Node.js |
let item: i32 = "value"; | let item: &str = "value"; | Type mismatch. | Rust |
for b in range(64)
print(b) | for b in range(64):
print(b) | Colon after for. | Python |
val z = 'output' | val z = "output" | Double quotes. | Kotlin |
$a = 49; if ($a = 49) {{}} | $a = 49; if ($a == 49) {{}} | Use ==. | PHP |
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