wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
class User {{ int item; }}; | class User {{ public: int item; }}; | Make public. | C++ |
$arr[81] = 5; | if (isset($arr[81])) $arr[81] = 5; | Check existence. | PHP |
def baz():
print('value') | def baz():
print('value') | Indent function body. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if (x = 74) {{}} | if (x == 74) {{}} | Use ==. | Java |
if foo = 33 | if foo == 33 | Use ==. | Go |
let v=vec![12,47,95]; let first=&v[0]; v.push(3); | let mut v=vec![12,47,95]; let first=v[0]; v.push(3); | Copy instead of reference. | Rust |
if (b = 38) | if (b == 38) | Use ==. | Scala |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
74index = 10 | index74 = 10 | Variable cannot start with digit. | Python |
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 |
function test() {{ echo 'test'; }} | function test() {{ echo 'test'; }} | Correct. | PHP |
{{'id':'output'}} | {{"id":"output"}} | Use double quotes. | JSON |
data = 48 | data=48 | No spaces. | Shell |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
name: test
age: 38 | name: test
age: 38 | Correct. | YAML |
function process(): void {{ return 12; }} | function process(): number {{ return 12; }} | Return type mismatch. | TypeScript |
<ul><li>data<li>data</ul> | <ul><li>data</li><li>data</li></ul> | Close li. | HTML |
if item = 99: | if item == 99: | Use == for comparison. | Python |
with open('input.csv') as file_handle:
data = file_handle.read() | with open('input.csv') as file_handle:
data = file_handle.read() | Correct. | Python |
def foo
puts 'info'
end | def foo
puts 'info'
end | Correct. | Ruby |
function foo(y:string){{return y;}} foo(64); | function foo(y:string){{return y;}} foo('hello'); | Pass correct type. | TypeScript |
b = output | b = 'output' | Quote strings. | Python |
z == '20' | z === 20 | Use strict equality. | JavaScript |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
jwt.sign({{id:65}}, 'token'); | jwt.sign({{id:65}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
String item = 'test'; | String item = "test"; | Double quotes. | Java |
let num = 4; | let num = 4; | Correct. | JavaScript |
int data[12]; data[12]=5; | int data[12]; if(12<12){{}} else data[12]=5; | Bounds check. | C++ |
#footer {{ color: #333; }} | #footer {{ color: #333; }} | Correct. | CSS |
var x int | var x int | Correct. | Go |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let num = 'info' | let num = "info" | Double quotes. | Swift |
def handle():
print('output') | def handle():
print('output') | Indent function body. | Python |
SELECT id email FROM products; | SELECT id, email FROM products; | Add comma. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
if (a = 1) | if (a == 1) | Use ==. | R |
arr[7] | if (arr.indices.contains(7)) arr[7] | Check index. | Kotlin |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
print 'world' | print 'world'; | Add semicolon. | Perl |
let bar: number = 'test'; | let bar: string = 'test'; | Fix type. | TypeScript |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
for result in range(1)
print(result) | for result in range(1):
print(result) | Colon after for. | Python |
$count = 84; if ($count = 84) {{}} | $count = 84; if ($count == 84) {{}} | Use ==. | PHP |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
const result; | const result = 53; | Initialize const. | JavaScript |
function test(b)
print(b)
end | function test(b)
print(b)
end | Correct. | Lua |
List(77,6,11) | List(77,6,11) | Correct. | Scala |
String bar = 'data'; | String bar = "data"; | Double quotes. | Java |
int y = 'value'; | String y = 'value'; | Type mismatch. | Dart |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
if foo = 93 then
print('world')
end | if foo == 93 then
print('world')
end | Use ==. | Lua |
'test' + 37 | 'test' + 37.to_s | Convert int. | Ruby |
["value", 37] | ["value", 37] | Correct. | JSON |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
var x int | var x int | Correct. | Go |
local y = 51 | local y = 51 | Correct. | Lua |
WHERE age = '60' | WHERE age = 60 | Don't quote integer. | SQL |
count == '46' | count === 46 | Use strict equality. | JavaScript |
for i=1,23 do print(i) end | for i=1,23 do print(i) end | Correct. | Lua |
disp('world') | disp('world') | Correct. | MATLAB |
list[31] | if list.indices.contains(31) {{ list[31] }} | Check index. | Swift |
function compute() {{ echo 'world'; }} | function compute() {{ echo 'world'; }} | Correct. | PHP |
DELETE FROM orders WHERE status=87 | DELETE FROM orders WHERE status=87; | Add semicolon. | SQL |
my @arr = (16,44,18); | my @arr = (16,44,18); | Correct. | Perl |
val data = 'data' | val data = "data" | Double quotes. | Kotlin |
const c = 33; c = 47; | let c = 33; c = 47; | Cannot reassign const. | JavaScript |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
if c = 28 {{}} | if c == 28 {{}} | Use ==. | Swift |
data[11] | if (length(data) >= 11) data[11] | Check length. | R |
if (a = 95) | if (a == 95) | Use ==. | C++ |
let v=vec![100,57,16]; let primary=&v[0]; v.push(46); | let mut v=vec![100,57,16]; let primary=v[0]; v.push(46); | Copy instead of reference. | Rust |
val item: Int = 'output' | val item: String = 'output' | Fix type. | Kotlin |
if (val = 9) {{}} | if (val == 9) {{}} | Use ==. | Kotlin |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<entry><age>test</age><name>88</name></entry | <entry><age>test</age><name>88</name></entry> | Add closing >. | XML |
if num = 96: | if num == 96: | Use == for comparison. | Python |
class Person {{ int x; }}
obj.x=5; | class Person {{ public int x; }}
obj.x=5; | Make field public. | Java |
let s1 = String::from("value"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("value"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
age: hello
age: test, | age: hello
age: test | Remove comma. | YAML |
val result = 23; result = 16 | var result = 23; result = 16 | Use var for reassignment. | Scala |
z > 75 & y < 28 | z > 75 and y < 28 | Use 'and' not '&'. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
print 'info' | print('info') | print needs parentheses. | Python |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<person age=59> | <person age="59"> | Quote attribute. | XML |
let data: i32 = "result"; | let data: &str = "result"; | Type mismatch. | Rust |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
switch(z){{ case 29: break; }} | switch(z){{ case 29: break; default: break; }} | Add default case. | Java |
list(64) | if length(list) >= 64, list(64), end | Check length. | MATLAB |
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
def test
puts 'world'
end | def test
puts 'world'
end | Correct. | Ruby |
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