conditional-statements

问题 I'm a beginner in coding. I was recently working with to create a chatting programme where a user will chat with my computer. Here is a part of the code: System.out.println("Hello, what's our name? My name is " + answer4); String a = scanner1.nextLine(); System.out.println("Ok, Hello, " + a + ", how was your day, good or bad?"); String b = scanner2.nextLine(); **if (b.equals("good"))** { //1 System.out.println("Thank goodness"); } else **if (b.equals("it was good"))** { //2 System.out.println

问题 I'm a beginner in R and I would like to know how to do the following task: I want to replace the missing values of my dataset by the median for all the columns of my dataset. However, for each column, I want the median of a certain category (depending on another column).My dataset is as follows structure(list(Country = structure(1:5, .Label = c("Afghanistan", "Albania", "Algeria", "Andorra", "Angola"), class = "factor"), CountryID = 1:5, Continent = c(1L, 2L, 3L, 2L, 3L), Adolescent.fertility

问题 I have a SQLite table with comments like: Id | replyId | commentID_parentID | usernameChannelId | channelId 1 | NULL | NULL | a | g 2 | NULL | NULL | b | k NULL | 1.k | 1 | a | p NULL | 1.p | 1 | c | i 3 | NULL | NULL | d | h NULL | 2.k | 2 | g | g and a table with channels like: I want to know which user (userChannelId) replied to which user. So I take a row with a comment and check if: Id == NULL? Then it's a reply -> get userChannelId where commentID_parentID == Id Id != NULL? Then it's a

问题 I have a SQLite table with comments like: Id | replyId | commentID_parentID | usernameChannelId | channelId 1 | NULL | NULL | a | g 2 | NULL | NULL | b | k NULL | 1.k | 1 | a | p NULL | 1.p | 1 | c | i 3 | NULL | NULL | d | h NULL | 2.k | 2 | g | g and a table with channels like: I want to know which user (userChannelId) replied to which user. So I take a row with a comment and check if: Id == NULL? Then it's a reply -> get userChannelId where commentID_parentID == Id Id != NULL? Then it's a

问题 I have created a parquet file with three columns (id, author, title) from database and want to read the parquet file with a condition (title='Learn Python'). Below mentioned is the python code which I am using for this POC. import pyarrow as pa import pyarrow.parquet as pq import pandas as pd import pyodbc def write_to_parquet(df, out_path, compression='SNAPPY'): arrow_table = pa.Table.from_pandas(df) if compression == 'UNCOMPRESSED': compression = None pq.write_table(arrow_table, out_path,

问题 I have created a parquet file with three columns (id, author, title) from database and want to read the parquet file with a condition (title='Learn Python'). Below mentioned is the python code which I am using for this POC. import pyarrow as pa import pyarrow.parquet as pq import pandas as pd import pyodbc def write_to_parquet(df, out_path, compression='SNAPPY'): arrow_table = pa.Table.from_pandas(df) if compression == 'UNCOMPRESSED': compression = None pq.write_table(arrow_table, out_path,

问题 I want to check if a boolean is true, then decide in the WHERE clause what condition to use. Say the boolean variable is @checkbool: SELECT * FROM TableA A WHERE --if @checkbool is true, run this A.Id = 123 --if @checkbool is false, run this A.Id <> 123 Is there a way to negate a condition? Like in C++ you can do if !(condition). If not, what is the best way to solve this problem? Thank you! 回答1: SQL's equivalent of ! in C is NOT . However, in your case you want something else: you need to

问题 I want to check if a boolean is true, then decide in the WHERE clause what condition to use. Say the boolean variable is @checkbool: SELECT * FROM TableA A WHERE --if @checkbool is true, run this A.Id = 123 --if @checkbool is false, run this A.Id <> 123 Is there a way to negate a condition? Like in C++ you can do if !(condition). If not, what is the best way to solve this problem? Thank you! 回答1: SQL's equivalent of ! in C is NOT . However, in your case you want something else: you need to

问题 suppose the cave system contains 100 caves, of which 90 caves are without a hidden treasure and 10 caves contain a buried gold object. In 70% of the caves with a hidden treasure, the Wumpus has left behind his usual stench from digging about and bumping into walls. In the remaining caves with hidden treasures in them, the Wumpus has left no trace, i.e. they are non-smelly. Furthermore, all the caves without a hidden treasure are free from smell, since the Wumpus has fled the cave system. The

问题 I'm not so experienced/elegant programmer. I hope my question is understandable. I have used java/c++ for most part of my life so my mind is object oriented. Then I learned python and I enjoyed very much functional mind. Now I'm approaching js. It is challenging because it is function based (and I liked it a lot), functional (with underscore I have a lot of pythonic iterutils methods) and asynchronous (it hurts). A lot of time I have some back-end sync procedural flow like: if exist(user):