You should absolutely use isEmpty(). Computing the size() of an arbitrary list could be expensive. Even validating whether it has any elements can be expensive, of course, but there’s no optimization for size() which can’t also make isEmpty() faster, whereas the reverse is not the case. For example, suppose you had a linked list structure … Read more
In Bash at least the following command tests if $var is empty: if [[ -z “$var” ]]; then # $var is empty, do what you want fi The command man test is your friend.
Misspellings are irritating, aren’t they? Check your spelling of empty, but then also try this: #!/bin/bash -e if [ -s diff.txt ]; then # The file is not-empty. rm -f empty.txt touch full.txt else # The file is empty. rm -f full.txt touch empty.txt fi I like shell scripting a lot, but one disadvantage of … Read more
Try using array_map() to apply the filter to every array in $array: $array = array_map(‘array_filter’, $array); $array = array_filter($array); Demo: http://codepad.org/xfXEeApj
Empty string, undefined, null, … To check for a truthy value: if (strValue) { // strValue was non-empty string, true, 42, Infinity, [], … } To check for a falsy value: if (!strValue) { // strValue was empty string, false, 0, null, undefined, … } Empty string (only!) To check for exactly an empty string, … Read more
You can use the :placeholder-shown pseudo class. Technically a placeholder is required, but you can use a space instead. input:not(:placeholder-shown) { border-color: green; } input:placeholder-shown { border-color: red; } <input placeholder=”Text is required” /> <input placeholder=” ” value=”This one is valid” /> <input placeholder=” ” />
How can I check for an empty/undefined/null string in JavaScript?