if-statement

问题 The STRATUM from OECD data is so long, for simplicity I put this name and would like to simplified it to a more short and precise naming as in the code below. pisaMas[,`:=` (SchoolType = c(ifelse(STRATUM == "National Secondary School", "Public", ifelse(STRATUM == "Religious School", "Religious", ifelse(STRATUM == "MOE Technical School", "Technical",0)))))] pisaMas[,table(SchoolType)] I would like to know if there are a simple way to this problems, using data.table package. 回答1: Current

问题 The STRATUM from OECD data is so long, for simplicity I put this name and would like to simplified it to a more short and precise naming as in the code below. pisaMas[,`:=` (SchoolType = c(ifelse(STRATUM == "National Secondary School", "Public", ifelse(STRATUM == "Religious School", "Religious", ifelse(STRATUM == "MOE Technical School", "Technical",0)))))] pisaMas[,table(SchoolType)] I would like to know if there are a simple way to this problems, using data.table package. 回答1: Current

问题 My codes allows the user to enter in a score from 1 to 100, which will either tell them that the score is "Good", "OK", "Moron", or "Invalid". But, when I compile these codes. The output has invalid in it too with the correct statement if it is more than 54. For example : if I enter in 55 it will say "OK" AND "Invalid". if I enter in 54 it will just say "Moron". Here are my codes: #define _CRT_SECURE_NO_WARNINGS #include<stdio.h> #include<stdlib.h> void main() { int score; printf("Enter a

问题 This question already has answers here : Is short-circuiting logical operators mandated? And evaluation order? (7 answers) How does C++ handle &&? (Short-circuit evaluation) [duplicate] (7 answers) Closed 6 years ago . Given two conditions with an && connection. I know that the order of evaluation is from left to right. But if the first condition resolves to false, it the second condition guaranteed to not get evaluated? #define SIZE bool array[SIZE]; int index; // play with variables // ...

问题 This question already has answers here : Is short-circuiting logical operators mandated? And evaluation order? (7 answers) How does C++ handle &&? (Short-circuit evaluation) [duplicate] (7 answers) Closed 6 years ago . Given two conditions with an && connection. I know that the order of evaluation is from left to right. But if the first condition resolves to false, it the second condition guaranteed to not get evaluated? #define SIZE bool array[SIZE]; int index; // play with variables // ...

问题 This question already has answers here : Is short-circuiting logical operators mandated? And evaluation order? (7 answers) How does C++ handle &&? (Short-circuit evaluation) [duplicate] (7 answers) Closed 6 years ago . Given two conditions with an && connection. I know that the order of evaluation is from left to right. But if the first condition resolves to false, it the second condition guaranteed to not get evaluated? #define SIZE bool array[SIZE]; int index; // play with variables // ...

问题 I'm having a problems with making if statements: <?php if (isset($detail) == 1) { ?> // code if detail variable exists and is equal to 1 <?php } else { ?> // code if detail variable doesn't exist or is not equal 1 <?php }?> For some reason this condition doesn't work. How could I fix the if condition, so it will work? 回答1: isset is a boolean operator which returns TRUE or FALSE . You don't need to compare it to 1 . if( isset($detail) ) As a side note, just because the variable is set, does

问题 I have a pandas dataframe that contains dates, items, and 2 values. All I'm looking to do is output another column that is the product of column A / column B if column B is greater than 0, and 0 if column B is equal to 0. date item A B C 1/1/2017 a 0 3 0 1/1/2017 b 2 0 0 1/1/2017 c 5 2 2.5 1/1/2017 d 4 1 4 1/1/2017 e 3 3 1 1/1/2017 f 0 4 0 1/2/2017 a 3 3 1 1/2/2017 b 2 2 1 1/2/2017 c 3 9 0.333333333 1/2/2017 d 4 0 0 1/2/2017 e 5 3 1.666666667 1/2/2017 f 3 0 0 this is the code I've written,

问题 I have a pandas dataframe that contains dates, items, and 2 values. All I'm looking to do is output another column that is the product of column A / column B if column B is greater than 0, and 0 if column B is equal to 0. date item A B C 1/1/2017 a 0 3 0 1/1/2017 b 2 0 0 1/1/2017 c 5 2 2.5 1/1/2017 d 4 1 4 1/1/2017 e 3 3 1 1/1/2017 f 0 4 0 1/2/2017 a 3 3 1 1/2/2017 b 2 2 1 1/2/2017 c 3 9 0.333333333 1/2/2017 d 4 0 0 1/2/2017 e 5 3 1.666666667 1/2/2017 f 3 0 0 this is the code I've written,

问题 I write my if {...} else {...} statement in R in the following way as I find it more readable. Testifelse = function(number1) { if(number1>1 & number1<=5) { number1 =1 } else if ((number1>5 & number1 < 10)) { number1 =2 } else { number1 =3 } return(number1) } According to ?Control : ... In particular, you should not have a newline between } and else to avoid a syntax error in entering a if ... else construct at the keyboard or via source ... the function above will cause syntax error, but