I have the following output:
time = 15:40:32.81
And I want to eliminate : and the . so that it looks like this:
15403281
I tried doing a
time.gsub(/\:\s/,'')
but that didn't work.
"15:40:32.81".gsub(/:|\./, "")
time = '15:40:32.81'
numeric_time = time.gsub(/[^0-9]+/, '')
# numeric_time will be 15403281
[^0-9] specifies a character class containing any character which is not a digit (^ at the beginning of a class negates it), which will then be replaced by an empty string (or, in other words, removed).
(Updated to replace \d with 0-9 for clarity, though they are equivalent).
If you want to be fancy and use an actual time object...
time = Time.now
time.strftime("%H%M%S") + time.usec.to_s[0,2]
# returns "15151788"
time.delete ':.'
But it'll edit your variable. If you don't want it:
time.dup.delete ':.'
Related
I need a generic way to convert classnames to lowercase with underscores. For example, I wish to convert the classname NewUserBatch to new_user_batch. How to do this?
Underscore.
>> 'NewUserBatch'.underscore
=> "new_user_batch"
It is included in Rails so if you don't use it, you can refer to its source code.
def underscore(camel_cased_word)
word = camel_cased_word.to_s.dup
word.gsub!(%r::/, '/')
word.gsub!(%r(?:([A-Za-z\d])|^)(#{inflections.acronym_regex})(?=\b|[^a-z])/) { "#{$1}#{$1 && '_'}#{$2.downcase}" }
word.gsub!(%r([A-Z\d]+)([A-Z][a-z])/,'\1_\2')
word.gsub!(%r([a-z\d])([A-Z])/,'\1_\2')
word.tr!("-", "_")
word.downcase!
word
end
In the simple case, where you only have non-namespaced class names, you can use this oneliner:
EDIT: updated with positive look-ahead assertion (thanks #vladr)
"MYRubyClassName".gsub(/(.)([A-Z](?=[a-z]))/,'\1_\2').downcase
# => "my_ruby_class_name"
This finds all uppercase chars that follow another char and in turn is followed by a lower case char, inserts underscore before it and then downcases everything.
Also a nice tip: to find if you know INPUT (NewUserBatch) and OUTPUT (new_user_batch) use the following method
"NewUserBatch".find_method("new_user_batch")
Apparently I still don't understand exactly how it works ...
Here is my problem: I'm trying to match numbers in strings such as:
910 -6.258000 6.290
That string should gives me an array like this:
[910, -6.2580000, 6.290]
while the string
blabla9999 some more text 1.1
should not be matched.
The regex I'm trying to use is
/([-]?\d+[.]?\d+)/
but it doesn't do exactly that. Could someone help me ?
It would be great if the answer could clarify the use of the parenthesis in the matching.
Here's a pattern that works:
/^[^\d]+?\d+[^\d]+?\d+[\.]?\d+$/
Note that [^\d]+ means at least one non digit character.
On second thought, here's a more generic solution that doesn't need to deal with regular expressions:
str.gsub(/[^\d.-]+/, " ").split.collect{|d| d.to_f}
Example:
str = "blabla9999 some more text -1.1"
Parsed:
[9999.0, -1.1]
The parenthesis have different meanings.
[] defines a character class, that means one character is matched that is part of this class
() is defining a capturing group, the string that is matched by this part in brackets is put into a variable.
You did not define any anchors so your pattern will match your second string
blabla9999 some more text 1.1
^^^^ here ^^^ and here
Maybe this is more what you wanted
^(\s*-?\d+(?:\.\d+)?\s*)+$
See it here on Regexr
^ anchors the pattern to the start of the string and $ to the end.
it allows Whitespace \s before and after the number and an optional fraction part (?:\.\d+)? This kind of pattern will be matched at least once.
maybe /(-?\d+(.\d+)?)+/
irb(main):010:0> "910 -6.258000 6.290".scan(/(\-?\d+(\.\d+)?)+/).map{|x| x[0]}
=> ["910", "-6.258000", "6.290"]
str = " 910 -6.258000 6.290"
str.scan(/-?\d+\.?\d+/).map(&:to_f)
# => [910.0, -6.258, 6.29]
If you don't want integers to be converted to floats, try this:
str = " 910 -6.258000 6.290"
str.scan(/-?\d+\.?\d+/).map do |ns|
ns[/\./] ? ns.to_f : ns.to_i
end
# => [910, -6.258, 6.29]
I have a string in Ruby:
str = "<TAG1>Text 1<TAG1>Text 2"
I want to use gsub to get a string like this:
want = "<TAG2>Text 1</TAG2><TAG2>Text2</TAG2>"
In other words, I want to save everything in between a <TAG1> and EITHER: 1) the next occurrence of a "<", or 2) the end of the string.
The best regex i could come up with was:
regex = /<TAG1>(.*)(?:<|$)/
But the problem with this is that it'll just match the entire str, where what I want is both matches within str. (In other words, it seems like the end of string char ($) seems to have precedence over the "<" character--is there a way to flip it around?
/<TAG1>([^<]*)/ will match that. If there's no < it'll go all the way to the end of the string. Otherwise it will stop when it hits a <. Your problem is that . matches < as well. An alternative way would be to do /<TAG1>(.*?)(?:<|$)/, which makes the * non-greedy.
I am trying to write a method that is the same as mysqli_real_escape_string in PHP. It takes a string and escapes any 'dangerous' characters. I have looked for a method that will do this for me but I cannot find one. So I am trying to write one on my own.
This is what I have so far (I tested the pattern at Rubular.com and it worked):
# Finds the following characters and escapes them by preceding them with a backslash. Characters: ' " . * / \ -
def escape_characters_in_string(string)
pattern = %r{ (\'|\"|\.|\*|\/|\-|\\) }
string.gsub(pattern, '\\\0') # <-- Trying to take the currently found match and add a \ before it I have no idea how to do that).
end
And I am using start_string as the string I want to change, and correct_string as what I want start_string to turn into:
start_string = %("My" 'name' *is* -john- .doe. /ok?/ C:\\Drive)
correct_string = %(\"My\" \'name\' \*is\* \-john\- \.doe\. \/ok?\/ C:\\\\Drive)
Can somebody try and help me determine why I am not getting my desired output (correct_string) or tell me where I can find a method that does this, or even better tell me both? Thanks a lot!
Your pattern isn't defined correctly in your example. This is as close as I can get to your desired output.
Output
"\\\"My\\\" \\'name\\' \\*is\\* \\-john\\- \\.doe\\. \\/ok?\\/ C:\\\\Drive"
It's going to take some tweaking on your part to get it 100% but at least you can see your pattern in action now.
def self.escape_characters_in_string(string)
pattern = /(\'|\"|\.|\*|\/|\-|\\)/
string.gsub(pattern){|match|"\\" + match} # <-- Trying to take the currently found match and add a \ before it I have no idea how to do that).
end
I have changed above function like this:
def self.escape_characters_in_string(string)
pattern = /(\'|\"|\.|\*|\/|\-|\\|\)|\$|\+|\(|\^|\?|\!|\~|\`)/
string.gsub(pattern){|match|"\\" + match}
end
This is working great for regex
This should get you started:
print %("'*-.).gsub(/["'*.-]/){ |s| '\\' + s }
\"\'\*\-\.
Take a look at the ActiveRecord sanitization methods: http://api.rubyonrails.org/classes/ActiveRecord/Base.html#method-c-sanitize_sql_array
Take a look at escape_string / quote method in Mysql class here
Consider the following string which is a C fragment in a file:
strcat(errbuf,errbuftemp);
I want to replace errbuf (but not errbuftemp) with the prefix G-> plus errbuf. To do that successfully, I check the character after and the character before errbuf to see if it's in a list of approved characters and then I perform the replace.
I created the following Ruby file:
line = " strcat(errbuf,errbuftemp);"
item = "errbuf"
puts line.gsub(/([ \t\n\r(),\[\]]{1})#{item}([ \t\n\r(),\[\]]{1})/, "#{$1}G\->#{item}#{$2}")
Expected result:
strcat(G->errbuf,errbuftemp);
Actual result
strcatG->errbuferrbuftemp);
Basically, the matched characters before and after errbuf are not reinserted back with the replace expression.
Anyone can point out what I'm doing wrong?
Because you must use syntax gsub(/.../){"...#{$1}...#{$2}..."} or gsub(/.../,'...\1...\2...').
Here was the same problem: werid, same expression yield different value when excuting two times in irb
The problem is that the variable $1 is interpolated into the argument string before gsub is run, meaning that the previous value of $1 is what the symbol gets replaced with. You can replace the second argument with '\1 ?' to get the intended effect. (Chuck)
I think part of the problem is the use of gsub() instead of sub().
Here's two alternates:
str = 'strcat(errbuf,errbuftemp);'
str.sub(/\w+,/) { |s| 'G->' + s } # => "strcat(G->errbuf,errbuftemp);"
str.sub(/\((\w+)\b/, '(G->\1') # => "strcat(G->errbuf,errbuftemp);"