How can I check if foo exists?
113905
How can I check whether a variable is defined in JavaScript?
23208
How can I check if a file exists in Perl?
46735
"which in ruby": Checking if program exists in $PATH from ruby
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How to check if a file exists in Go?
39834
Check whether files in a file list exist in a certain directory
69406
Check if file exists but prevent 404 error in console from showing up
74109
How to verify in Javascript Object Model if a List Exists
9397
Oracle: If Table Exists
16672
Shell script check if file exists?
37438
How do I use the CoffeeScript existential operator to check some object properties for undefined?
17040
Check if an array is empty or exists
27233
Nested If Exist statements in Batch File
35245
How do I check if file exists in jQuery or pure JavaScript?
69750
MySQL check if a table exists without throwing an exception
39682
Check if limit exists and its value
157654
Checking if a key exists in a JavaScript object?
71238
Check if a property exists in a class