String Comparisons
by Steven Noonan
June 15, 2005
Note: OPS =
Operations
Per Second
I actually wrote a function which improves the speed of StrComp if the strings
are not of the same length (if the lengths aren't the same, it cannot be
the same string). My function is called StringComp. You will see a huge
difference in speed when we get to non-identical strings.
When doing string comparisons, and you want case insensitivity, you should
always use StrComp, instead of an "if LCase$(StringOne) = LCase$(StringTwo)".
Below is a comparison of the speeds.
| Identical Strings (Case insensitive) | ||
| LCase$(StringOne) = LCase$(StringTwo) | StrComp(StringOne, StringTwo, vbTextCompare) = 0 | StringComp(StringOne, StringTwo) |
| 526,534 OPS | 1,500,911 OPS | 1,394,779 OPS |
However, whenever you are doing a case-sensitive string comparison, you should use the StringOne = StringTwo, as it is significantly faster (shown below).
| Identical Strings (Case sensitive) | ||
| StringOne = StringTwo | StrComp(StringOne, StringTwovbTextCompare) = 0 | StringComp(StringOne, StringTwo) |
| 3,305,785 OPS | 1,501,243 OPS | 1,400,304 OPS |
And if the strings are not identical (differential lengths), you do not see a dramatic difference between the methods, except for my StringComp method.
| Non-Identical Strings (Case insensitive) | ||
| LCase$(StringOne) = LCase$(StringTwo) | StrComp(StringOne, StringTwo, vbTextCompare) = 0 | StringComp(StringOne, StringTwo) |
| 510,484 OPS | 1,369,553 OPS | 15,010,511 OPS |
| Non-Identical Strings (Case sensitive) | ||
| StringOne = StringTwo | StrComp(StringOne, StringTwo, vbTextCompare) = 0 | StringComp(StringOne, StringTwo) |
| 3,396,174 OPS | 1,390,758 OPS | 15,857,913 OPS |
As is obvious, comparing the length before comparing the string will help the speed greatly.
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