In unit test I would like to hard code a block of lines as a string.
In C# I would do
var sb = new StringBuilder();
sb.AppendLine("myline1");
sb.AppendLine("myline2");
sb.AppendLine("myline3");
Since I converted to F# I tried to minimize the usage of .Net method by using bprintf instead, but somehow there is no bprintfn support which seems strange to me.
It is tedious to add \r\n at the end of each line manually.
Or is there any better way than StringBuilder?
Little known feature: you can indeed indent string content - by ending each line with a backslash. Leading spaces on the following line are stripped:
let poem = "The lesser world was daubed\n\
By a colorist of modest skill\n\
A master limned you in the finest inks\n\
And with a fresh-cut quill.\n"
You will still need to include \n or \n\r at line ends though (as done in the example above), if you want these embedded in your final string.
Edit to answer #MiloDCs question:
To use with sprintf:
let buildPoem character =
sprintf "The lesser world was daubed\n\
By a colorist of modest skill\n\
A master limned %s in the finest inks\n\
And with a fresh-cut quill.\n" character
buildPoem "you"
buildPoem "her"
buildPoem "him"
If you are under F# 3.0, triple-quoted strings may be the answer:
let x = """
myline1
myline2
myline3"""
I'm surprised nobody has mentioned this:
[ "My first line"
"second line"
"another line" ]
|> String.concat "\n"
You can create directly multi-line string literals in F#:
let multiLineStr =
"myline1
myline2
myline3"
and C#:
var multiLineStr =
#"myline1
myline2
myline3";
I think there is no problem with using StringBuilder in F# as you did.
There is a function fprintfn in Printf module, so you can use it with a StringWriter object:
let sw = new StringWriter()
fprintfn sw "myline1"
fprintfn sw "myline2"
fprintfn sw "myline3"
sw.ToString()
I like fprintf and fprintfn since they are flexible. You can write to console output by supplying stdout instead.
You could define your own bprintfn function:
let bprintfn bldr fmt =
(bldr, fmt) ||> Printf.kbprintf bldr.AppendLine
Or, to define a multi-line literal you could use triple-quotes as bytebuster suggested or a "verbatim literal," which begins with # (see Strings on MSDN).
I'm out of touch with F#, but you might be able to do adapt my normal approach:
['line1', 'line2', 'line3'].join('\n'); //javascript
StringUtils.join(Arrays.asList("line1", "line2", "line3"), "\n")); // java, using Apache Commons Lang
Related
I'm very new to groovy (here working on Jenkinsfile)
One of my coworkers uses a Match Operator to check a condition. But I find it not readable and hard to maintain.
Original Match Operator:
PROJECT_NAME = 'projectA' // User Input from Jenkins params normaly
if ( "${PROJECT_NAME}" ==~ /projectA|projectB|projectC|projectD/) { // The real line is 300 Char long
// Do stuff
}
There is 15 projects in total, i've shorten up the line because it was too long. So every time he needs to add a project name, he appends at the start or end of his regex.
Also, those project name are in a list before.
projects = ['projectA',
'projectB',
'projectC',
'projectD']
Could there be a way to use this list to build the regex?
Here is what I tried:
string_regex = "/"
for (project in projects) {
string_regex = string_regex + project + "|"
}
string_regex = string_regex.substring(0, string_regex.length() - 1)
string_regex = string_regex + "/"
print "${string_regex}\n"
if ("${PROJECT_NAME}" ==~ string_regex) {
print "Well Done you did it\n"
// Do stuff
}
But saddly it doesn't seems to work, since I'm using a string?
EDIT: I found out that I could use the contains method from a list in Groovy. In my case, it fixes my original problem. But I'm still curious on how to build such regex with strings.
if (projects.contains(PROJECT_NAME)) {
// Do stuff
}
You can join your projects and then turn the string into a regexp via Pattern.compile(). For good measure use Pattern.quote() to safe-guard against chars in your project names with "meaning" in regexp.
import java.util.regex.Pattern
def projects = ['projectA',
'projectB',
'projectC',
'projectD']
def re = Pattern.compile(projects.collect{ Pattern.quote it }.join("|"))
['projectA', 'projectX'].each{
println it ==~ re
}
// -> true
// -> false
For what it's worth, I came to like the Groovy matching operators for their compact syntax. If you learn about them and practice for a short bit, you will probably get to like them, too.
Regardless, for a simple check, on whether a String is part of a list, there is a much simpler way in Groovy than using full blown regexp : the in operator, e.g.:
def projects = ['projectA',
'projectB',
'projectC',
'projectD']
['projectA', 'projectX'].each {
println "${it} is ${it in projects ? 'IN' : 'NOT IN'} the project list"
}
which yields e.g.:
projectA is IN the project list
projectX is NOT IN the project list
More info on that operator and many other aspects of the Groovy language from the always excellent MrHaki here
Of course, if you need to account for case differences, etc... you have to massage the code a bit, but at some point, a regexp might be warranted.
If you have already an collection, you should nearly always use an collection operator; E.g. replace
if ( "${PROJECT_NAME}" ==~ /projectA|projectB|projectC|projectD/) {
with:
if (PROJECT_NAME in projects) {
Much easier to read and understand, no? 😉
simple question that I hope has a simple answer
I want to store a formatted string to pass later to function call. I would like to have line breaks baked into one long string rather than send a string for each line. So for example
b = f'hello \n world'
b
this gives me 'hello \n world' which is not what I want.
How can I do this in a compact manner. I would prefer to avoid joins or something like that with a newline separator.
Thanks in advance.
I am fairly new to Puppet and Ruby. Most likely this question has been asked before but I am not able to find any relevant information.
In my puppet code I will have a string variable retrieved from the fact hostname.
$n="$facts['hostname'].ex-ample.com"
I am expecting to get the values like these
DEV-123456-02B.ex-ample.com,
SCC-123456-02A.ex-ample.com,
DEV-123456-03B.ex-ample.com,
SCC-999999-04A.ex-ample.com
I want to perform the following action. Change the string to lowercase and then replace the
-02, -03 or -04 to -01.
So my output would be like
dev-123456-01b.ex-ample.com,
scc-123456-01a.ex-ample.com,
dev-123456-01b.ex-ample.com,
scc-999999-01a.ex-ample.com
I figured I would need to use .downcase on $n to make everything lowercase. But I am not sure how to replace the digits. I was thinking of .gsub or split but not sure how. I would prefer to make this happen in a oneline code.
If you really want a one-liner, you could run this against each string:
str
.downcase
.split('-')
.map
.with_index { |substr, i| i == 2 ? substr.gsub(/0[0-9]/, '01') : substr }
.join('-')
Without knowing what format your input list is taking, I'm not sure how to advise on how to iterate through it, but maybe you have that covered already. Hope it helps.
Note that Puppet and Ruby are entirely different languages and the other answers are for Ruby and won't work in Puppet.
What you need is:
$h = downcase(regsubst($facts['hostname'], '..(.)$', '01\1'))
$n = "${h}.ex-ample.com"
notice($n)
Note:
The downcase and regsubst functions come from stdlib.
I do a regex search and replace using the regsubst function and replace ..(.)$ - 2 characters followed by another one that I capture at the end of the string and replace that with 01 and the captured string.
All of that is then downcased.
If the -01--04 part is always on the same string index you could use that to replace the content.
original = 'DEV-123456-02B.ex-ample.com'
# 11 -^
string = original.downcase # creates a new downcased string
string[11, 2] = '01' # replace from index 11, 2 characters
string #=> "dev-123456-01b.ex-ample.com"
Something like that is coming in:
str="Hello;this;is;a;text"
What I do want as result is this:
result="72:101:108:108:111;116:104:105:115;..."
which should be the Text in ASCII.
You could use string matching to get each word separated by ; and then convert, concat:
local str = "Hello;this;is;a;text"
for word in str:gmatch("[^;]+") do
ascii = table.pack(word:byte(1, -1))
local converted = table.concat(ascii, ":")
print(converted)
end
The output of the above code is:
72:101:108:108:111
116:104:105:115
105:115
97
116:101:120:116
I'll leave the rest of work to you. Hint: use table.concat.
Here is another approach, which exploits that fact that gsub accepts a table where it reads replacements:
T={}
for c=0,255 do
T[string.char(c)]=c..":"
end
T[";"]=";"
str="Hello;this;is;a;text"
result=str:gsub(".",T):gsub(":;",";")
print(result)
Another possibility:
function convert(s)
return (s:gsub('.',function (s)
if s == ';' then return s end
return s:byte()..':'
end)
:gsub(':;',';')
:gsub(':$',''))
end
print(convert 'Hello;this;is;a;text')
Finding certain character or string (such as ";") can be done by using string.find - https://www.lua.org/pil/20.1.html
Converting character to its ASCII code can be done by string.byte - https://www.lua.org/pil/20.html
What you need to do is build a new string using two functions mentioned above. If you need more string-based functions please visit official Lua site: https://www.lua.org/pil/contents.html
Okay...I got way further, but I can't find how to return a string made up of two seperate strings like
str=str1&" "&str2
I have a strings:
str = "this is a great place...."
I want to print only 30 words from this string. How to do that?
Use split and take methods:
val str = "this is a great place...."
str.split("\\W").take(30).mkString(" ")
// res0: String = this is a great place
You could just do something like:
"""(\b\w+\b\W*){0,30}""".r findPrefixOf "this is a great place...."
Or using a different notation:
"""(\b\w+\b\W*){0,30}""".r.findPrefixOf("this is a great place....")
Here is some pseudo code you can work with
Split string using the split method into an Array[String] of the words.
Iterate across the array and concatenate the words together that you want to include
Print out the string
I can't think of any external libraries or built-in functions that will do that for you. You will need to write your own code to do this.