You do not need more functions. The solution can be simpler from my understanding in 6 lines: pollutantmean <- function(directory, pollutant, id = 1:10) { filenames <- sprintf(“%03d.csv”, id) filenames <- paste(directory, filenames, sep=”https://stackoverflow.com/”) ldf <- lapply(filenames, read.csv) df=ldply(ldf) # df is your list of data.frames mean(df[, pollutant], na.rm = TRUE) } 2 solved Calculate … Read more
Let’s split your code… Part1: create function do_twice(f), that will run f() two times. def do_twice(f): f() f() Part2: create a function called print_spam() that will print() the word “spam” def print_spam(): print(‘spam’) Part3: call the function print_spam() inside the do_twice() funtion do_twice(print_spam) This way, your code will ‘think’ something like this: “Oh he called … Read more
First one is three-element tuple. Second one is some string. Third one is same three-element tuple, since in this context parentheses are redundant. Small code snippet will be enough to prove it: g1 = (3, 4, 5) g2 = “(3, 4, 5)” g3 = 3, 4, 5 type(g1) # <type ‘tuple’> type(g2) # <type ‘str’> … Read more
To avoid Warn: Possible unhandled Promise Rejection (id:0) useEffect(() => { fetchData(); }, []); async function fetchData(){ try{ const requestArray = await Promise.all(ids?.map((id) => { return fetch(`https://jsonplaceholder.typicode.com/posts/${id}`) .then((response) => response.json()) .then((dataLoc) => { return dataLoc.title; }) .catch((error) => console.error(error)); })); console.log(JSON.stringify(requestArray)); setDataLoc(requestArray); } catch (error) { console.log(error); } } solved How to get multiple API … Read more
With JavaScript 1.6 / ECMAScript 5 you can use the native filter method of an Array in the following way to get an array with unique values: function onlyUnique(value, index, self) { return self.indexOf(value) === index; } // usage example: var a = [‘a’, 1, ‘a’, 2, ‘1’]; var unique = a.filter(onlyUnique); console.log(unique); // [‘a’, … Read more
You should add a key to each child as well as each element inside children. This way React can handle the minimal DOM change. In your code, each <TableRowItem key={item.id} data={item} columns={columnNames}/> is trying to render some children inside them without a key. Check this example. Try removing the key={i} from the <b></b> element inside … Read more
For custom-delimited date formats, you have to pull out the date (or time) components from a DateTimeFormat object (which is part of the ECMAScript Internationalization API), and then manually create a string with the delimiters you want. To do this, you can use DateTimeFormat#formatToParts. You could destructure the array, but that is not ideal, as … Read more
If the interpretation I gave in my comment is correct, one way to allow the user to call functions you define is to put those functions in a dictionary, keyed by their name. Then you can examine that dict to see if i belongs to it, and call the function if appropriate. def buclick(): i … Read more
Use the using statement, just like you have shown, yes it is the elegant way using (var something = Method2()) { Method1(something); } Or if you will using (var something = Method2()) Method1(something); Anything else would be unusual and confusing (ie disposing it in your method1)… As pointed out by the comments, unless this was … Read more
You can group by Cattle SELECT Cattle, SUM(Liter) AS TotalLiter FROM NewMilk GROUP BY Cattle ORDER BY Cattle See: SQL GROUP BY Statement Or if you need the total of only one specific cattle type SELECT SUM(Liter) AS TotalLiter FROM NewMilk WHERE Cattle=”Cow” You can execute a SQL command returning rows like this string sql … Read more
The syntax for the append method is as follow: list.append(obj) So you should replace students.append() by: students.append(tmp) Moreover, your print_info and input_info methods are not displaying the properties of a given student, but the properties of the class Student itself (which are always the same for every instance of the class). You should fix that. 3 solved Create … Read more
First, create an object using the given data and collect the keys and their values. { A: [1, 2], C: [“FOO”, “BAR”] } Then, get the Cartesian product of this object. The function getCartesian separates all key/value pairs and builds a new Cartesian product by iterating over the values, if an array with objects call … Read more
The quickest way is to set .isUserInteractionEnabled to false on your UITextView or UITextField solved How to disable a user’s ability to select text in a UITextField or UITextView?
Using the built-in csv library to iterate over each row’s values will do the trick: import csv with open(‘data.csv’) as csvfile: csvin = csv.DictReader(csvfile) for row in csvin: if row[‘col2:’] == “true” and row[‘col3:’] == “false”: print(row[‘col1:’]) Output result: 1 0 solved How can i read a csv based on data in other columns? [closed]
I guess you are reading from data reader. You will have to check if the value is null or DBNull and then you can call to string method. string user_guid = dr[“user_guid”] != DBNull.Value && dr[“user_guid”] != null ? dr[“user_guid”].ToString() : null ; Hope this helps. solved How to avoid Tostring exception if string is … Read more