conditional-statements | 易学教程

Removing the IE10 Select Element Arrow

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So, with Mozilla and WebKit I have a half-decent solution replacing the arrow on the select box using appearance: none; and having a parent element. In IE for the most part I disabled this feature. For IE10 I can't actually disable it since my conditional comments don't actually work. Here is my markup:       <html> <!--<![endif]--

Assign class boolean value in Python

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问题 If statements in Python allow you to do something like: if not x: print "X is false." This works if you're using an empty list, an empty dictionary, None, 0, etc, but what if you have your own custom class? Can you assign a false value for that class so that in the same style of conditional, it will return false? 回答1: You need to implement the __nonzero__ method on your class. This should return True or False to determine the truth value: class MyClass(object): def __init__(self, val): self

C++ multiple strings inside an if statement

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I'm having an issue trying to check against multiple possibilities in an if statement. The user inputs a string, and then I check that string against multiple possibilities. if (theString == "Seven" || "seven" || "7") { theInt = 7; cout << "You chose: " << theInt << endl; } else if (theString == "Six" || "six" || "6") { theInt = 6; cout << "You chose: " << theInt << endl; } So there's just a quick example of what I'm trying to accomplish. In my program, these if statements are in a function, and I am using #include [string]. (I'm not even sure if "6" or "7" is possible, but I can't even test

resetting cumsum if value goes to negative in r

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问题 ve <- c(17, -9, 9, -17, 17, -17, 11, -9, 16, -18, 17, 0, 0, -18, 17, 0, 0, -17, 14, -14, 17, -2, 0, -15, 9, -9, 17, -16, 16, -17, 17, -17, 17, -17, 17, -17, 17, -8, 7, -16, 17, -14, 14, -10, 10, -16, 16, -10, 10, -12, 12, -11, 11, -17, 17, -17, 17, -9, 8, -17, 17, -17, 17, -16, 16, -17, 17, -8, 8, -9, 9, -17, 17, -17, 17, -13, 13, -10, 7, -10, 13, -16, 17, -13, 13, -13, 13, -9, 8, -17, 17, -10, 9, -17, 17, -17, 17, -16, 16, -10, 10, -15, 15, -14, 14, -14, 15, -13, 13, -9, 9, -13, 13, -12, 12,

How to manage a table/matrix to obtain information using conditions

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Ive been thinking about what is the best way to solve this, any advise? The table/matrix X is: X <- read.table(text = " a b c d e 0 27 0 28 8 1 14 24 32 33 0 4 22 25 27 0 3 7 26 34 0 28 33 31 21 0 16 17 24 18 1 3 19 0 12 0 2 23 5 24 2 17 22 22 10 0 35 15 17 2", header = TRUE, stringsAsFactors = FALSE) or using matlab: X =[ 0 27 0 28 8 1 14 24 32 33 0 4 22 25 27 0 3 7 26 34 0 28 33 31 21 0 16 17 24 18 1 3 19 0 12 0 2 23 5 24 2 17 22 22 10 0 35 15 17 2]; How could I obtain a table/matrix A and B which contains: rows and columns accumulated each 5 values until the maximum value of table X -> in

How to ignore NA in ifelse statement

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I came to R from SAS, where numeric missing is set to infinity. So we can just say: positiveA = A > 0; In R, I have to be verbose like: positiveA <- ifelse(is.na(A),0, ifelse(A > 0, 1, 0)) I find this syntax is hard to read. Is there anyway I can modify ifelse function to consider NA a special value that is always false for all comparison conditions? If not, considering NA as -Inf will work too. Similarly, setting NA to '' (blank) in ifelse statement for character variables. Thanks. This syntax is easier to read: x <- c(NA, 1, 0, -1) (x > 0) & (!is.na(x)) # [1] FALSE TRUE FALSE FALSE (The

Conditional PowerShell parameters

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问题 Is there a way to have some of the parameters mandatory based on some condition (for example, if one of the parameters is absent or false) in a PowerShell function? My idea is to be able to call a function in two ways. A concrete example is a function that gets a list from SharePoint - I should be able to call it with relative URL of the list (one and only parameter) OR with a web URL and a list display name (two parameters, both mandatory, but only if list relative URL is not used). 回答1: As

#if, #else, #end if … what do the hash signs mean in VBA?

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I'm writing some code which will check to see if a file is available to be checked out of SharePoint and, if it isn't, alert the user and tell them that the file is in use by someone else and who has it is in use by. I came across a piece of code at this site: http://www.xcelfiles.com/IsFileOpen.html#anchor_37 The code itself is pretty good and seems to work in test scenarios so I am planning to adapt it for my purposes but I'm having trouble understanding some of the syntax being used because I've never seen the likes of it before. #If Not VBA6 Then '// Xl97 For i = j - 1 To 1 Step -1 If Mid

Using conditional statements inside 'expect'

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I need to automate logging into a TELNET session using expect , but I need to take care of multiple passwords for the same username. Here's the flow I need to create: Open TELNET session to an IP Send user-name Send password Wrong password? Send the same user-name again, then a different password Should have successfully logged-in at this point... For what it's worth, here's what I've got so far: #!/usr/bin/expect spawn telnet 192.168.40.100 expect "login:" send "spongebob\r" expect "password:" send "squarepants\r" expect "login incorrect" { expect "login:" send "spongebob\r" expect "password:

Simpler way to check if variable is not equal to multiple string values?

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Current Codes: <?php // See the AND operator; How do I simplify/shorten this line? if( $some_variable !== 'uk' && $some_variable !== 'in' ) { // Do something } ?> And: <?php // See the OR operator; How do I simplify/shorten this line? if( $some_variable !== 'uk' || $some_variable !== 'in' ) { // Do something else } ?> Is there a simpler (i.e. shorter) way to write the two conditions? NOTE: Yes, they are different, and I am expecting different ways to shorten the codes. For your first code, you can use a short alteration of the answer given by @ShankarDamodaran using in_array() : if ( !in_array