b.santos/abap-cheat-sheets
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Update

Browse Source
This commit is contained in:
danrega
2024-05-03 16:33:59 +02:00
parent d40807c68d
commit 455025e033
10 changed files with 386 additions and 76 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
07_String_Processing.md
View File

@@ -150,7 +150,7 @@ DATA: flag TYPE c LENGTH 1, "Built-in type
char1 TYPE c_type, "Local type
str2 LIKE str1, "Deriving type from a local data object
str3 TYPE str_type, "Local type
char2 TYPE s_toairp, "DDIC type (used e. g. for a field in a demo table)
tstmp TYPE timestampl, "DDIC type
char3 TYPE zdemo_abap_flsch-carrid. "Using the type of a DDIC table component
"You may also encounter declarations with type c and the length
@@ -1651,13 +1651,25 @@ Character Sets, Ranges, Subgroups and Lookarounds
| `(?!...)` | Negative lookahead, returns characters that are not followed by a specified pattern without including this pattern | `a(?!b)` | abc ade | abc <ins>**a**</ins>de | <ins>**a**</ins>bc ade |
| `(?<=...)` | Positive lookbehind, returns characters that are preceded by a specified pattern without including this pattern | `(?<=\s)c` | ab c abcd | ab <ins>**c**</ins> abcd (it is preceded by a blank) | ab c ab<ins>**c**</ins>d |
| `(?<!...)` | Negative lookbehind, returns characters that are not preceded by a specified pattern without including this pattern | `(?<!\s)c` | ab c abcd | ab c ab<ins>**c**</ins>d (it is not preceded by a blank) | ab <ins>**c**</ins> abcd |
| `\n` | Backreference, refers to a previous capturing group; n represents the number of the group index that starts with 1 | `(a.)(\w*)\1` | abcdefabghij | <ins>**abcdefab**</ins>ghij <br>Note: Capturing group 1 holds `ab` in the example. The second capturing group captures all word characters until `ab` is found. | <ins>**ab**</ins>cdefabghij |
| `\1` | Backreference, refers to a previous capturing group; 1 represents the number of the group index (the group index starts with 1) | `(a.)(\w*)\1` | abcdefabghij | <ins>**abcdefab**</ins>ghij <br>Note: Capturing group 1 holds `ab` in the example. The second capturing group captures all word characters until `ab` is found. | <ins>**ab**</ins>cdefabghij |
| `\K` | Resets the starting point of a match, i.e. findings are excluded from the final match | `a.\Kc` | abcd | ab<ins>**c**</ins>d | <ins>**abc**</ins>d |
> **💡 Note**<br>
> - Subgroups are useful in replacements. By using an expression with `$` and a number, such as `$1`, you can refer to a specific group. For example, you have a string `abcde`. A PCRE expression might be
`(ab|xy)c(d.)`, where two subgroups are specified within two pairs of parentheses. In a replacement pattern, you can refer to the first group with `$1` and the second group with `$2`. Thus, the replacement pattern `$2Z$1` results in `deZab`.
> - `(?:x)` creates a group but it is not captured. Example regular expression: `(?:ab)(ap)`. Example string: 'abap'. It matches 'abap', but `$1` will only contain 'ap'.
> - Note that `.` does not include new line feeds among others. If you want to capture a new line, you can use `\n` as regular expression. The following example string includes a new line. All content between the HTML p tags should be replaced. You could use a regular expression to capture any character or new line as follows:
> ```abap
> DATA(str_a) = |<p>Hallo\n</p><p>Ciao!</p><p>Salut.</p>|.
> DATA(str_b) = str_a.
>
> REPLACE ALL OCCURRENCES OF PCRE `(<p>)(.*?)(<\/p>)` IN str_a WITH `$1Hi$3`.
> "<p>Hallo
> "</p><p>Hi</p><p>Hi</p>
>
> "Regular expression: any character or a new line with zero or more repretitions
> REPLACE ALL OCCURRENCES OF PCRE `(<p>)(.|\n)*?(<\/p>)` IN str_b WITH `$1Hi$3`.
> "<p>Hi</p><p>Hi</p><p>Hi</p>
Anchors and Positions