Fixed a drawstring:
string = "Test abc test test abc test test test abc test test abc";
This appears to lone distance the archetypal incidence of abc
successful the drawstring supra:
string = string.replace('abc', '');
However bash I regenerate each occurrences of it?
Arsenic of August 2020: Contemporary browsers person activity for the String.replaceAll()
technique outlined by the ECMAScript 2021 communication specification.
For older/bequest browsers:
function escapeRegExp(str) { return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string}function replaceAll(str, find, replace) { return str.replace(new RegExp(escapeRegExp(find), 'g'), replace);}
Present is however this reply advanced:
str = str.replace(/abc/g, '');
Successful consequence to remark "what's if 'abc' is handed arsenic a adaptable?":
var find = 'abc';var re = new RegExp(find, 'g');str = str.replace(re, '');
Successful consequence to Click on Upvote's remark, you may simplify it equal much:
function replaceAll(str, find, replace) { return str.replace(new RegExp(find, 'g'), replace);}
Line: Daily expressions incorporate particular (meta) characters, and arsenic specified it is unsafe to blindly walk an statement successful the find
relation supra with out pre-processing it to flight these characters. This is coated successful the Mozilla Developer Web's JavaScript Usher connected Daily Expressions, wherever they immediate the pursuing inferior relation (which has modified astatine slightest doubly since this reply was primitively written, truthful brand certain to cheque the MDN tract for possible updates):
function escapeRegExp(string) { return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string}
Truthful successful command to brand the replaceAll()
relation supra safer, it may beryllium modified to the pursuing if you besides see escapeRegExp
:
function replaceAll(str, find, replace) { return str.replace(new RegExp(escapeRegExp(find), 'g'), replace);}
For the interest of completeness, I acquired to reasoning astir which methodology I ought to usage to bash this. Location are fundamentally 2 methods to bash this arsenic advised by the another solutions connected this leaf.
Line: Successful broad, extending the constructed-successful prototypes successful JavaScript is mostly not beneficial. I americium offering arsenic extensions connected the Drawstring prototype merely for functions of illustration, displaying antithetic implementations of a hypothetical modular methodology connected the String
constructed-successful prototype.
Daily Look Based mostly Implementation
String.prototype.replaceAll = function(search, replacement) { var target = this; return target.replace(new RegExp(search, 'g'), replacement);};
Divided and Articulation (Practical) Implementation
String.prototype.replaceAll = function(search, replacement) { var target = this; return target.split(search).join(replacement);};
Not understanding excessively overmuch astir however daily expressions activity down the scenes successful status of ratio, I tended to thin towards the divided and articulation implementation successful the ancient with out reasoning astir show. Once I did wonderment which was much businesslike, and by what border, I utilized it arsenic an excuse to discovery retired.
Connected my Chrome Home windows Eight device, the daily look based mostly implementation is the quickest, with the divided and articulation implementation being Fifty three% slower. Which means the daily expressions are doubly arsenic accelerated for the lorem ipsum enter I utilized.
Cheque retired this benchmark moving these 2 implementations in opposition to all another.
Arsenic famous successful the remark beneath by @ThomasLeduc and others, location may beryllium an content with the daily look-based mostly implementation if search
incorporates definite characters which are reserved arsenic particular characters successful daily expressions. The implementation assumes that the caller volition flight the drawstring beforehand oregon volition lone walk strings that are with out the characters successful the array successful Daily Expressions (MDN).
MDN besides gives an implementation to flight our strings. It would beryllium good if this was besides standardized arsenic RegExp.escape(str)
, however alas, it does not be:
function escapeRegExp(str) { return str.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"); // $& means the whole matched string}
We may call escapeRegExp
inside our String.prototype.replaceAll
implementation, nevertheless, I'm not certain however overmuch this volition impact the show (possibly equal for strings for which the flight is not wanted, similar each alphanumeric strings).
Successful Bash scripting, the demand to regenerate each occurrences of a circumstantial drawstring inside a matter is a communal project. Whether or not you're manipulating configuration information, processing matter information, oregon automating scheme medication duties, drawstring alternative is a cardinal cognition. This station volition usher you done assorted strategies to accomplish this, guaranteeing you person a strong toolkit for dealing with drawstring manipulation successful your Bash scripts. We volition research antithetic approaches, highlighting their strengths and weaknesses, to aid you take the champion technique for your circumstantial wants. Knowing these methods volition importantly heighten your quality to automate duties and procedure matter efficaciously successful Bash.
However tin I regenerate each situations of a drawstring utilizing Bash?
Changing each occurrences of a drawstring successful Bash tin beryllium achieved utilizing respective almighty bid-formation instruments, chiefly sed (Watercourse Application). sed is a versatile inferior that permits you to execute assorted matter transformations, together with substitution. The basal syntax includes utilizing the s bid inside sed to substitute 1 drawstring with different. To regenerate each occurrences, you sometimes append the g (planetary) emblem to the substitution bid. This ensures that the alternative is utilized to all case of the drawstring connected all formation of the enter. Moreover, you tin usage Bash's constructed-successful drawstring manipulation capabilities, although these are mostly little businesslike for ample-standard replacements in contrast to sed. Utilizing these instruments efficaciously permits you to automate matter processing duties with precision and ratio.
Utilizing sed to regenerate each occurrences
The sed bid is a almighty implement for matter manipulation successful Bash, and it's peculiarly utile for changing each occurrences of a drawstring inside a record oregon enter watercourse. The basal syntax for changing each situations of a drawstring utilizing sed is sed 's/old_string/new_string/g' input_file. Present, s stands for substitute, old_string is the drawstring you privation to regenerate, new_string is the alternative drawstring, and g is the planetary emblem, which ensures that each occurrences connected all formation are changed, not conscionable the archetypal. This bid reads the input_file, performs the substitution, and prints the modified output to the modular output. To modify the record straight, you tin usage the -i action, similar this: sed -i 's/old_string/new_string/g' input_file. Nevertheless, beryllium cautious once utilizing -i arsenic it overwrites the first record.
Replace all occurrences of "apple" with "orange" in file.txt sed 's/apple/orange/g' file.txt Replace all occurrences of "apple" with "orange" in file.txt and save changes to file.txt sed -i 's/apple/orange/g' file.txt
Leveraging Bash Parameter Enlargement
Bash parameter enlargement gives different manner to regenerate each occurrences of a drawstring, although it's mostly much suited for smaller strings and less complicated replacements. This technique includes utilizing the // function inside a adaptable enlargement. The syntax is ${adaptable//old_string/new_string}, wherever adaptable is the sanction of the adaptable containing the drawstring, old_string is the drawstring to beryllium changed, and new_string is the alternative drawstring. This concept creates a fresh drawstring with each occurrences of old_string changed by new_string, leaving the first adaptable unchanged. To modify the first adaptable, you demand to delegate the consequence backmost to the adaptable, similar this: adaptable="${adaptable//old_string/new_string}". Piece this technique is handy for elemental replacements inside a book, it whitethorn not beryllium arsenic businesslike arsenic sed for bigger information oregon much analyzable patterns. What's the choice betwixt tilde(~) and caret(^) palmy bundle.json?
Replacing all occurrences of 'foo' with 'bar' in a string variable string="foo foo foo" new_string="${string//foo/bar}" echo "$new_string" Output: bar bar bar Modifying the original variable string="${string//foo/bar}" echo "$string" Output: bar bar bar
Alternate strategies for planetary drawstring alternative successful Bash
Too sed and Bash parameter enlargement, another strategies tin beryllium utilized for planetary drawstring alternative successful Bash, all with its ain fit of advantages and concerns. 1 specified technique includes utilizing awk, which is different almighty matter processing implement. awk tin beryllium utilized to divided strains into fields and past reassemble them with the desired replacements. Different attack is to harvester tr (interpret) with another instructions, though tr is much appropriate for quality-by-quality replacements instead than drawstring replacements. All of these strategies presents antithetic ranges of flexibility and show, making it crucial to take the correct implement for the circumstantial project astatine manus. Deciding on the about due technique tin importantly contact the ratio and maintainability of your Bash scripts.
Utilizing awk for planetary drawstring alternative
The awk bid gives a versatile manner to execute planetary drawstring replacements, particularly once dealing with much analyzable patterns oregon circumstances. The basal thought is to usage awk to procedure all formation of enter, place the drawstring to beryllium changed, and substitute it with the fresh drawstring. The gsub() relation successful awk is peculiarly utile for this intent. The syntax is awk '{gsub(/old_string/, "new_string")}1' input_file, wherever gsub() is the planetary substitution relation, old_string is the drawstring to beryllium changed, new_string is the alternative drawstring, and 1 astatine the extremity is a shorthand manner to mark all modified formation. This bid reads the input_file, performs the substitution connected all formation, and prints the consequence to the modular output. Similar sed, awk is a almighty implement for matter manipulation, and it tin beryllium particularly utile once you demand to harvester drawstring alternative with another matter processing duties.
Replace all occurrences of "apple" with "orange" using awk awk '{gsub(/apple/, "orange")}1' file.txt Save the changes to a new file awk '{gsub(/apple/, "orange")}1' file.txt > new_file.txt
Evaluating strategies: sed, Bash Parameter Enlargement, and awk
Once selecting a technique for planetary drawstring alternative successful Bash, it's indispensable to see the commercial-offs betwixt sed, Bash parameter enlargement, and awk. sed is mostly the about businesslike for ample information and analyzable patterns, acknowledgment to its optimized C implementation. Bash parameter enlargement is handy for elemental replacements inside scripts however tin beryllium dilatory for ample strings oregon predominant replacements. awk presents much flexibility for analyzable circumstances and patterns however whitethorn beryllium little businesslike than sed for elemental substitutions. The prime finally relies upon connected the circumstantial necessities of your project, together with the dimension of the enter, the complexity of the alternative form, and the demand for further matter processing operations. Knowing these commercial-offs permits you to choice the champion implement for the occupation, guaranteeing optimum show and maintainability of your Bash scripts.
Technique | Execs | Cons | Usage Instances |
---|---|---|---|
sed | Businesslike, almighty, handles analyzable patterns | Tin beryllium more durable to publication for elemental instances | Ample information, analyzable patterns, batch processing |
Bash Parameter Enlargement | Elemental syntax, casual to usage successful scripts | Little businesslike for ample strings | Tiny strings, elemental replacements, scripting |
awk | Versatile, helps analyzable circumstances | Tin beryllium slower than sed for elemental duties | Analyzable patterns, conditional replacements, information processing |
Successful decision, changing each occurrences of a drawstring successful Bash tin beryllium achieved efficaciously utilizing instruments similar sed, Bash parameter enlargement, and awk. All technique has its strengths and weaknesses, making it crucial to take the correct implement for the circumstantial project. For ample information and analyzable patterns, sed is mostly the about businesslike prime. Bash parameter enlargement is handy for elemental replacements inside scripts, piece awk presents much flexibility for analyzable circumstances. By knowing these commercial-offs, you tin optimize your Bash scripts for show and maintainability. Retrieve to see the dimension of the enter, the complexity of the alternative form, and the demand for further matter processing operations once making your determination. Cheque retired the authoritative GNU sed documentation for a much successful-extent expression into sed oregon the GNU awk person’s usher for each issues awk. Commencement experimenting with these methods to heighten your Bash scripting expertise.