for-loop

问题 This question already has answers here : Scoping in Python 'for' loops (6 answers) Closed 4 years ago . Consider this example: for iter in xrange(10): myvar = iter print myvar # 9 Here myvar is clearly outside the loop? But it is still accessible. If this is Perl, it will throw an error. What's the reason behind such feature in Python? Is it harmful? What's the best practice then, to declare a variable before looping? 回答1: There is no new scope created by the for loop (Ruby also behaves the

问题 There are 2 tables EMPLOYEES and DEPARTMENTS with department_id as primary key for DEPARTMENTS and foreign key on EMPLOYEES . I want to print all the employee names that belong to a particular department. I know it can be easily achieved by JOINS or EXPLICIT cursors. I thought why not try with FOR loop and a IMPLICIT cursors. My question is if it is syntactically correct to write INTO like this. If so why is not assigning any values? DECLARE emp_dept_id employees.department_id%TYPE; emp_emp

问题 When I use an Iterator of Object I use a while loop (as written in every book learning Java, as Thinking in Java of Bruce Eckel): Iterator it=... while(it.hasNext()){ //... } but sometime i saw than instead somebody use the for loop : Iterator it=... for (Iterator it=...; it.hasNext();){ //... } I don't' understand this choice: I use the for loop when I have a collection with ordinal sequence (as array) or with a special rule for the step (declared generally as a simple increment counter++ ).

问题 I would like to confirm if this is a bug on PMD? How do I file a ticket if it is. public static void main(final String[] args) { for (final String string : args) { string.getBytes(); //UR Anomaly } for (int i = 0; i < args.length; i++) { args[i].getBytes(); } } Lines 1-3 are being flagged as UR anomaly, while rewriting it to iterate with a local variable is fine. Would like to eliminate as much PMD violations, but it is inconvenient to have to resort to old loop construct as a workaround.

问题 I would like to confirm if this is a bug on PMD? How do I file a ticket if it is. public static void main(final String[] args) { for (final String string : args) { string.getBytes(); //UR Anomaly } for (int i = 0; i < args.length; i++) { args[i].getBytes(); } } Lines 1-3 are being flagged as UR anomaly, while rewriting it to iterate with a local variable is fine. Would like to eliminate as much PMD violations, but it is inconvenient to have to resort to old loop construct as a workaround.

问题 For some reason the following code doesn't work. var a1 = Math.floor(Math.random()*4+1); //Answer2 for(a2 = 0; a2 != a1 && a2 != 0; a2 = Math.floor(Math.random()*4+1)){ alert(a2); } I'm trying to get "a2" to be a int from 1-4 but not equivalent to "a1". What's wrong? Thanks in advance!!! EDIT: Thank you all for your help! Here's my final result: var a1, a2; a1 = Math.floor(Math.random()*4+1); a2 = a1; while(a2 == a1){ a2 = Math.floor(Math.random() * 3 + 1); alert(a2); } 回答1: How about a while

问题 For some reason the following code doesn't work. var a1 = Math.floor(Math.random()*4+1); //Answer2 for(a2 = 0; a2 != a1 && a2 != 0; a2 = Math.floor(Math.random()*4+1)){ alert(a2); } I'm trying to get "a2" to be a int from 1-4 but not equivalent to "a1". What's wrong? Thanks in advance!!! EDIT: Thank you all for your help! Here's my final result: var a1, a2; a1 = Math.floor(Math.random()*4+1); a2 = a1; while(a2 == a1){ a2 = Math.floor(Math.random() * 3 + 1); alert(a2); } 回答1: How about a while

问题 This is a question from coderbyte’s easy set. Many people asked about it already, but I’m really curious about what’s wrong with my particular solution (I know it’s a pretty dumb and inefficient one..) Original question: Have the function LetterCountI(str) take the str parameter being passed and return the first word with the greatest number of repeated letters. For example: "Today, is the greatest day ever!" should return greatest because it has 2 e's (and 2 t's) and it comes before ever

问题 I am trying to run the below code using for loop but i am getting syntax error. Please help. Input Format: The first line of the input contains an integer N, indicating the number of integers. The next line contains N space-separated integers that form the array A. read n sum=0 for (( i=1; i<= "$n" ; i++ )) do read val sum ^= $val; done echo $sum Below is the error message solution.sh: line 4: ((: i<= 1 : syntax error: invalid arithmetic operator (error token is " ") 回答1: The printf "%s" "$n"

问题 I have these nested for-loops that I would like to convert to parfor: row = 1; for i = 5 : 0.2 : 5.4 col = 1; for j = 2 : 0.5 : 2.5 matrx(row, col) = i * j; col = col + 1; end row = row + 1; end Does anyone any way in which this would be possible? 回答1: I hope you're only displaying an extremely simplified version of your code, but anyways, the secret to parfor can be found by listening to Matlab numerous messages and reading the documentation. Start by learning good Matlab coding practices,