concatenation

问题 I've built an Xpath expression by concatenating strings in VB6: strXPath = "xDOC.selectNodes(" & """/GroupType1""" & ").item(" & CStr(i) & ").selectNodes(" & """/OperationStageCollection/OperationStage""" & ").length" "i" is an integer used to index into I want to evaluate strXPath to get a loop counter, for example: n = CInt(strXPath) n is declared as Integer; strXPath is declared as string. VB6 throws a Type Mismatch error on the above evaluation expression. I must be missing something

问题 As per Pandas 0.19.2 documentation, I can provide keys argument to create a resulting multi-index DataFrame. An example (from pandas documents ) is : result = pd.concat(frames, keys=['x', 'y', 'z']) How would I concat the dataframe so that I can provide the keys at the column level instead of index level ? What I basically need is something like this : where df1 and df2 are to be concat. 回答1: This is supported by keys parameter of pd.concat when specifying axis=1 : df1 = pd.DataFrame(np

问题 Tried to concatenate strings diagonally from this post how to alternatively concatenate 3 strings, but was not successful. My input is: a<-c("a1","a2","a3") b<-c("b1","b2","b3") c<-c("c1","c2","c3") My expected output would be "a1" "b2" "c3" "a2" "b3" "a3" How to get the above from c(rbind(a,b,c)) 回答1: How about ordering the vector by values derived by the row and columns after setting the lower diagonal to missing mat <- rbind(a,b,c) mat[lower.tri(mat)] <- NA na.omit(mat[order(col(mat) - row

问题 This question already has answers here : Why allow concatenation of string literals? (10 answers) Closed 5 years ago . #include <iostream> #include <string> int main() { std::string str = "hello " "world" "!"; std::cout << str; } The following compiles, runs, and prints: hello world! see live It seems as though the string literals are being concatenated together, but interestingly this can not be done with operator + : #include <iostream> #include <string> int main() { std::string str =

问题 The compiler doesn't seem to infer that the integer variables are passed as string literals into the concat! macro, so I found the stringify! macro that converts these integer variables into string literals, but this looks ugly: fn date(year: u8, month: u8, day: u8) -> String { concat!(stringify!(month), "/", stringify!(day), "/", stringify!(year)).to_string() } 回答1: concat! takes literals and produces a &'static str at compile time. You should use format! for this: fn date(year: u8, month:

问题 I work with a lot of dtype="str" data. I've been trying to build a simple graph as in https://www.tensorflow.org/versions/master/api_docs/python/train.html#SummaryWriter. For a simple operation, I wanted to concatenate strings together using a placeholder as in (How to feed a placeholder?) Does anyone know how to merge string tensors together? import tensorflow as tf sess = tf.InteractiveSession() with tf.name_scope("StringSequence") as scope: left = tf.constant("aaa",name="LEFT") middle = tf

问题 I work with a lot of dtype="str" data. I've been trying to build a simple graph as in https://www.tensorflow.org/versions/master/api_docs/python/train.html#SummaryWriter. For a simple operation, I wanted to concatenate strings together using a placeholder as in (How to feed a placeholder?) Does anyone know how to merge string tensors together? import tensorflow as tf sess = tf.InteractiveSession() with tf.name_scope("StringSequence") as scope: left = tf.constant("aaa",name="LEFT") middle = tf

问题 Is there a better way to do this? Note: part1 , part2 and part3 are string variables defined elsewhere (they can be null). def list = [part1, part2, part3] list.removeAll([null]) def ans = list.join() The desired result is a concatenated string with null values left out. 回答1: You can do this: def ans = [part1, part2, part3].findAll({it != null}).join() You might be able to shrink the closure down to just {it} depending on how your list items will evaluate according to Groovy Truth, but this

问题 I'm using mysql/php/apache . I have the following situation: 2 tables where I need to compare some information, it is no problem if I use INNER JOIN, but I have a problem in my columns. table 1 -> invoices_account table 2 -> invoices_payable on my invoices_account I have this fields: id, categ, categ_name, code, name, active, essential on my invoices_payable I have: id, ..(all my fields).. , reference the value of my field reference in invoices_payable is the same value of categ and code in

问题 I have a list of email addresses, and I need to send an email notification to each address. I'd like to do this in blocks of 25 addresses at a time. Is there any quick way in a functional language like F# to "fold" (concatenate) 25 emails addresses together... each separated by a semicolon. I know there is the String.Split method in .NET, but I need to concat 25 at a time. What is the most elegant way to perform this in F#? 回答1: Here's a way to break into groups of at most N: // break a