variable-assignment

问题 I have a kind of 'basics' question about php. In the example code for fgets, it has this snippet as an example of reading through a file's contents: while (($buffer = fgets($handle, 4096)) !== false) { echo $buffer; } How is it that the statement ($buffer = fgets($handle, 4096)) can have a value? Is it a kind of assignment+evaluation of $buffer ? I mean, how does it get its value? Is there a name for this? I notice its using strict comparison, so do all assignments evaluate to a boolean true

问题 I get unexpected result for this simple JavaScript assignment statement: var t = 1 == 1 ? 1 : 0; undefined I would have expected to get 1 assigned to v instead. Same result if you do var t = (1 == 1 ? 1 : 0); undefined Can somebody explain why this does not work as expected? 回答1: The result of evaluating var t = 1 == 1 ? 1 : 0; in, say, the Firebug console will be undefined . However, the value of t will be 1 as expected. Try outputting t after the assignment. Firebug will print the result

问题 I am currently writing a program that reads records from a txt file and prints the data on the screen as such: GRADE REPORT NAME COURSE GRADE ----------------------------------------------------------- JOE FRITZ AMERICAN GOVERNMENT B CALCULUS I A COMPUTER PROGRAMMING B ENGLISH COMPOSITION A Total courses taken = 4 LANE SMITH FUND. OF DATA PROCESSING B INTERMEDIATE SWIMMING A INTRO. TO BUSINESS C Total courses taken = 3 JOHN SPITZ CHOIR C COLLEGE STATISTICS B ENGLISH LITERATURE D INTRO. TO

问题 I encounter a strange thing while coding in Xcode 4.3. The nature of problem is described in the title. I mentioned this together with a storyboard connection problem in another post. The connection problem seems to go away at least for now. But the value assign problem persists. So I put it up as a new post. -(void) setQuestion:(NSString *)question { _question = question; self.questionLabel.text = question; NSLog(@"The quesion is %@",question); NSLog(@"The quesion label text is %@",self

问题 I have a friend who told me the following but I couldn't give a good reason why. someArray =......... int a; for(int i=0; i < someArray; i++) { a=someArray.get(i).length(); // Do something } He told me that he declared a outside of the for loop in order to avoid frequent garbage collection. I thought declaring a inside of the for loop is more readable and thread safe. However I couldn't disagree that different instances a no of iteration will be garbage collected if it's declared inside of

问题 I want to do v$session@remotedatabase where remotedatabase is a variable for a dblink address. Is that possible? I'm using Apex 4 and trying to get temporary space on all databases. Current query select 'Total temp space available in :Database is '||sum(bytes)/1024/1024 ||' mb' from v$tempfile@:Database yeilds ORA-01729: database link name expected because the variable isn't resolved correcltly? I'm quite new to SQL, sorry 回答1: You would need to use dynamic SQL in order to have the database

问题 I want to know why the following codes work? #!/usr/bin/env python3 import sys class Car(): def __init__(self): pass if __name__ == '__main__': c = Car() c.speed = 3 c.time = 5 print(c.speed, c.time) I accidentally found that I don't have to init attributes in init . I learn from every tutor I have to put assignment in init like below. #!/usr/bin/env python3 import sys class Car(): def __init__(self): self.speed = 3 self.time = 5 if __name__ == '__main__': c = Car() print(c.speed, c.time) If

问题 In C we are allowed to assign the value of one structure variable to other if they are of the same type.In accordance with that, in my following program I am allowed to use s1=s2 when both are struct variables of the same type.But why then I am not allowed to use s1={59,3.14} after that? I know we can't assign a string "Test" to a character array arr other than in the initialization statement because for the string "Test" ,it decomposes to type char* during assignment and hence there is a

问题 var width = 10; var data = image.data; var height = 10; for ( var x = 0; x < width; x++ ) { for ( var y = 0; y < height; y++ ) var index = 4 * (y * height + x); // 0 var local_variable = ArbitraryClassInstance.getBrightness(x, y); // 0 data[ index ] = ArbitraryClassInstance.getBrightness(x, y); // 0 for both index/call data[ index + 1 ] = ArbitraryClassInstance.getBrightness(x, y); // 0 for both index/call } } context.putImageData(image, 0, 0); Both index and local_variable are equalled to

问题 I was trying to understand how Session.run() works in Tensorflow flow. I know that Session.run() runs the sub-graph specified by the "fetch" argument we give it. Since depending on which part of the sub-graph is executed first we might get different results, I was trying to see if that is really the case. Suppose we compare the output of this code: import tensorflow as tf x = tf.Variable(42) assign1 = tf.assign(x, 13) assign2 = tf.assign(x, 14) with tf.Session() as sess: sess.run(tf.global