string-interpolation | 易学教程

Python: format string with custom delimiters [duplicate]

阅读更多关于 Python: format string with custom delimiters [duplicate]

问题 This question already has answers here : How can I print literal curly-brace characters in python string and also use .format on it? (12 answers) Closed last year . EDITED I have to format a string with values from a dictionary but the string already contains curly brackets. E.g.: raw_string = """ DATABASE = { 'name': '{DB_NAME}' } """ But, of course, raw_string.format(my_dictionary) results in KeyErro. Is there a way to use different symbols to use with .format() ? This is not a duplicate of

PowerShell outputting array items when interpolating within double quotes

阅读更多关于 PowerShell outputting array items when interpolating within double quotes

I found some strange behavior in PowerShell surrounding arrays and double quotes. If I create and print the first element in an array, such as: $test = @('testing') echo $test[0] Output: testing Everything works fine. But if I put double quotes around it: echo "$test[0]" Output: testing[0] Only the $test variable was evaluated and the array marker [0] was treated literally as a string. The easy fix is to just avoid interpolating array variables in double quotes, or assign them to another variable first. But is this behavior by design? EBGreen So when you are using interpolation, by default it

bash variable interpolation separate variables by a hyphen or underscore

阅读更多关于 bash variable interpolation separate variables by a hyphen or underscore

问题 This is a simple script just to see if the file has been downloaded. On this script the find command always evaluated to zero - even if it didn\'t find anything. So I commented it out. on the filename=\"day_CTRwFEES_hoo01M_\" I had to add an underscore to the end of the filename. Using an underscore $filename_$yesterday.CSV to separate the two did not work. - I had to take out the underscore, add it to the filename and then combine the variables to make it work like this - $filename$yesterday

PHP variable interpolation vs concatenation [duplicate]

阅读更多关于 PHP variable interpolation vs concatenation [duplicate]

问题 This question already has an answer here: Should I use curly brackets or concatenate variables within strings? 3 answers What is the difference between the two following methods (performance, readability, etc.) and what do you prefer? echo \"Welcome {$name}s!\" vs. echo \"Welcome \".$name.\"!\"; 回答1: Whatever works best for you works... But if you want to go for speed use this: echo 'Welcome ', $name, '!'; The single quotes tell PHP that no interpretation is needed, and the comma tells PHP to

String variable interpolation Java [duplicate]

阅读更多关于 String variable interpolation Java [duplicate]

问题 This question already has an answer here: How to format strings in Java 6 answers String building in Java confounds me. I abhore doing things like: url += \"u1=\" + u1 + \";u2=\" + u2 + \";u3=\" + u3 + \";u4=\" + u4 + \";\"; url += \"x=\" + u1 + \";y=\" + u2 + \";z=\" + u3 + \";da1=\" + u4 + \";\"; url += \"qty=1;cost=\" + orderTotal + \";ord=\" + orderId + \"?\"; Or, using StringBuilder, something like this: url.append(\"u1=\"); url.append(u1); url.append(\";u2=\"); url.append(u2); url

Using a Variable (PowerShell) inside of a command

阅读更多关于 Using a Variable (PowerShell) inside of a command

问题 $computer = gc env:computername # Argument /RU \'$computer\'\\admin isn\'t working. SchTasks /create /SC Daily /tn \"Image Verification\" /ST 18:00:00 /TR C:\\bdr\\ImageVerification\\ImageVerification.exe /RU \'$computer\'\\admin /RP password Basically I need to provide the computer name in the scheduled task... Thank you in advance! 回答1: Single quoted strings will not expand variables in PowerShell. Try a double quoted string e.g.: "$computer\admin" 回答2: use the command 'hostname' to get the

String Interpolation vs String.Format

阅读更多关于 String Interpolation vs String.Format

问题 Is there a noticable performance difference between using string interpolation: myString += $\"{x:x2}\"; vs String.Format()? myString += String.Format(\"{0:x2}\", x); I am only asking because Resharper is prompting the fix, and I have been fooled before. 回答1: Noticable is relative. However: string interpolation is turned into string.Format() at compile-time so they should end up with the same result. There are subtle differences though: as we can tell from this question, string concatenation

How can I manually interpolate string escapes in a Perl string?

阅读更多关于 How can I manually interpolate string escapes in a Perl string?

问题 In perl suppose I have a string like \'hello\\tworld\\n\' , and what I want is: \'hello world \' That is, \"hello\", then a literal tab character, then \"world\", then a literal newline. Or equivalently, \"hello\\tworld\\n\" (note the double quotes). In other words, is there a function for taking a string with escape sequences and returning an equivalent string with all the escape sequences interpolated? I don\'t want to interpolate variables or anything else, just escape sequences like \\x ,

Use YAML with variables

阅读更多关于 Use YAML with variables

问题 Are variables within YAML files possible? For example: theme: name: default css_path: compiled/themes/$theme.name layout_path: themes/$theme.name In this example, how can theme: name: default be used in other settings? What is the syntax? 回答1: I had this same question, and after a lot of research, it looks like it's not possible . The answer from cgat is on the right track, but you can't actually concatenate references like that. Here are things you can do with "variables" in YAML (which are

How to postpone/defer the evaluation of f-strings?

阅读更多关于 How to postpone/defer the evaluation of f-strings?

问题 I am using template strings to generate some files and I love the conciseness of the new f-strings for this purpose, for reducing my previous template code from something like this: template_a = \"The current name is {name}\" names = [\"foo\", \"bar\"] for name in names: print (template_a.format(**locals())) Now I can do this, directly replacing variables: names = [\"foo\", \"bar\"] for name in names: print (f\"The current name is {name}\") However, sometimes it makes sense to have the