awk:awk_loops
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| awk:awk_loops [2020/05/06 19:53] – peter | awk:awk_loops [2020/07/15 09:30] (current) – external edit 127.0.0.1 | ||
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| ===== For loops ===== | ===== For loops ===== | ||
| - | The **for** statement performs some initialization action, then it checks the condition. | + | A **for** statement performs some initialization action, then it checks the condition. |
| If the condition is true, it executes actions, thereafter it performs increment or decrement operation. | If the condition is true, it executes actions, thereafter it performs increment or decrement operation. | ||
| Line 33: | Line 33: | ||
| ===== While Loop ===== | ===== While Loop ===== | ||
| - | The while loop keeps executing the action until a particular logical condition evaluates to true. | + | A **while** loop keeps executing the action until a particular logical condition evaluates to true. |
| AWK first checks the condition; if the condition is true, it executes the action. | AWK first checks the condition; if the condition is true, it executes the action. | ||
| Line 39: | Line 39: | ||
| This process repeats as long as the loop condition evaluates to true. | This process repeats as long as the loop condition evaluates to true. | ||
| - | < | + | < |
| awk 'BEGIN {i = 1; while (i < 6) { print i; ++i } }' | awk 'BEGIN {i = 1; while (i < 6) { print i; ++i } }' | ||
| </ | </ | ||
| Line 57: | Line 57: | ||
| ===== Do-While Loop ===== | ===== Do-While Loop ===== | ||
| - | The **do-while** loop is similar to the while loop, except that the test condition is evaluated at the end of the loop. | + | A **do-while** loop is similar to the while loop, except that the test condition is evaluated at the end of the loop. |
| In a do-while loop, the action statement gets executed at least once even when the condition statement evaluates to false. | In a do-while loop, the action statement gets executed at least once even when the condition statement evaluates to false. | ||
| - | < | + | < |
| awk 'BEGIN {i = 1; do { print i; ++i } while (i < 6) }' | awk 'BEGIN {i = 1; do { print i; ++i } while (i < 6) }' | ||
| </ | </ | ||
| Line 79: | Line 79: | ||
| ===== Break Statement ===== | ===== Break Statement ===== | ||
| - | A Break is used to end the loop execution. | + | **Break** is used to end the loop execution. |
| - | < | + | < |
| awk 'BEGIN { | awk 'BEGIN { | ||
| sum = 0; for (i = 0; i < 20; ++i) { | sum = 0; for (i = 0; i < 20; ++i) { | ||
| Line 108: | Line 108: | ||
| ===== Continue Statement ===== | ===== Continue Statement ===== | ||
| - | The **continue** statement is used inside a loop to skip to the next iteration of the loop. | + | A **continue** statement is used inside a loop to skip to the next iteration of the loop. |
| It is useful when you wish to skip the processing of some data inside the loop. | It is useful when you wish to skip the processing of some data inside the loop. | ||
| - | < | + | < |
| awk 'BEGIN { | awk 'BEGIN { | ||
| for (i = 1; i <= 20; ++i) { | for (i = 1; i <= 20; ++i) { | ||
| Line 145: | Line 145: | ||
| If no argument is supplied, exit returns a zero. | If no argument is supplied, exit returns a zero. | ||
| - | < | + | < |
| awk 'BEGIN { | awk 'BEGIN { | ||
| sum = 0; for (i = 0; i < 20; ++i) { | sum = 0; for (i = 0; i < 20; ++i) { | ||
awk/awk_loops.1588794800.txt.gz · Last modified: 2020/07/15 09:30 (external edit)