negate

SQL WHERE condition is not equal to?

由 大兔子大兔子 提交于 2019-11-27 10:14:14
问题 Is it possible to negate a where clause? e.g. DELETE * FROM table WHERE id != 2; 回答1: You can do like this DELETE FROM table WHERE id NOT IN ( 2 ) OR DELETE FROM table WHERE id <> 2 As @Frank Schmitt noted, you might want to be careful about the NULL values too. If you want to delete everything which is not 2 (including the NULLs) then add OR id IS NULL to the WHERE clause. 回答2: Your question was already answered by the other posters, I'd just like to point out that delete from table where id

How do I negate a test with regular expressions in a bash script?

由 て烟熏妆下的殇ゞ 提交于 2019-11-27 09:38:25
问题 Using GNU bash (version 4.0.35(1)-release (x86_64-suse-linux-gnu), I would like to negate a test with Regular Expressions. For example, I would like to conditionally add a path to the PATH variable, if the path is not already there, as in: TEMP=/mnt/silo/bin if [[ ${PATH} =~ ${TEMP} ]] ; then PATH=$PATH; else PATH=$PATH:$TEMP; fi TEMP=/mnt/silo/Scripts: if [[ ${PATH} =~ ${TEMP} ]] ; then PATH=$PATH; else PATH=$PATH:$TEMP; fi TEMP=/mnt/silo/local/bin if [[ ${PATH} =~ ${TEMP} ]] ; then PATH=

Negate if condition in bash script

由 落花浮王杯 提交于 2019-11-26 18:00:00
问题 I'm new to bash and I'm stuck at trying to negate the following command: wget -q --tries=10 --timeout=20 --spider http://google.com if [[ $? -eq 0 ]]; then echo "Sorry you are Offline" exit 1 This if condition returns true if I'm connected to the internet. I want it to happen the other way around but putting ! anywhere doesn't seem to work. 回答1: You can choose: if [[ $? -ne 0 ]]; then # -ne: not equal if ! [[ $? -eq 0 ]]; then # -eq: equal if [[ ! $? -eq 0 ]]; then ! inverts the return of the

How can I negate the return-value of a process?

由 こ雲淡風輕ζ 提交于 2019-11-26 16:03:16
问题 I'm looking for a simple, but cross-platform negate -process that negates the value a process returns. It should map 0 to some value != 0 and any value != 0 to 0, i.e. the following command should return "yes, nonexistingpath doesn't exist": ls nonexistingpath | negate && echo "yes, nonexistingpath doesn't exist." The ! - operator is great but unfortunately not shell-independent. 回答1: Previously, the answer was presented with what's now the first section as the last section. POSIX Shell

How to negate a method reference predicate

由 冷暖自知 提交于 2019-11-26 12:45:42
In Java 8, you can use a method reference to filter a stream, for example: Stream<String> s = ...; long emptyStrings = s.filter(String::isEmpty).count(); Is there a way to create a method reference that is the negation of an existing one, i.e. something like: long nonEmptyStrings = s.filter(not(String::isEmpty)).count(); I could create the not method like below but I was wondering if the JDK offered something similar. static <T> Predicate<T> not(Predicate<T> p) { return o -> !p.test(o); } Anton Balaniuc Predicate.not( … ) java-11 offers a new method Predicate#not So you can negate the method

Negating a backreference in Regular Expressions

由 断了今生、忘了曾经 提交于 2019-11-26 12:25:14
问题 if a string has this predicted format: value = \"hello and good morning\" Where the \" (quotations) might also be \' (single quote), and the closing char (\' or \") will be the same as the opening one. I want to match the string between the quotation marks. \\bvalue\\s*=\\s*([\"\'])([^\\1]*)\\1 (the two \\s are to allow any spaces near the = sign) The first \"captured group\" (inside the first pair of brackets) - should match the opening quotation which should be either \' or \" then - I\'m

How to negate a method reference predicate

由 血红的双手。 提交于 2019-11-26 04:07:54
问题 In Java 8, you can use a method reference to filter a stream, for example: Stream<String> s = ...; long emptyStrings = s.filter(String::isEmpty).count(); Is there a way to create a method reference that is the negation of an existing one, i.e. something like: long nonEmptyStrings = s.filter(not(String::isEmpty)).count(); I could create the not method like below but I was wondering if the JDK offered something similar. static <T> Predicate<T> not(Predicate<T> p) { return o -> !p.test(o); } 回答1
订阅 negate