Comparing Strings

Table of Contents

Both Excel VBA and Python support string comparison using relational operators or dedicated functions.

Using Relational Operators

[Excel VBA] Relational operators (<, <=, >, >=, =, <>) compare strings character-by-character from left to right. Example:

code.vba 
Sub Test()
    Dim strA As String, strB As String
    strA = "abc"
    strB = "abc123"
    Debug.Print strA < strB  ' True(shorter string is "smaller" if prefixes match)
End Sub

[Python] Use ==/!= (value equality), is (object identity), in/not in (substring check).

code.python 
>>> a = 'abc'
>>> b = 'abc123'
>>> a == b          # False(values differ)
>>> a != b          # True
>>> a is b          # False(different objects)
>>> 'abc' in b      # True (substring exists)
>>> 'd' not in b    # True (substring does not exist)

Using Functions

[Excel VBA] Use StrComp to compare strings. Returns:

-1: String1 < String2

0: String1 = String2

1: String1 > String2

Null: Either string is Null.

Syntax:

code.vba 
StrComp(String1, String2[, Compare])

Example:

code.vba 
Sub Test2()
    Dim strA As String, strB As String, strC As String
    Dim varComp1, varComp2, varComp3
    strA = "abc"
    strB = "abc123"
    strC = "ABc"

    varComp1 = StrComp(strA, strB)                  ' Case-sensitive: -1(abc < abc123)
    varComp2 = StrComp(strA, strC)                  ' Case-sensitive: 1(abc > ABc)
    varComp3 = StrComp(strA, strC, vbTextCompare)   ' Case-insensitive: 0(abc = ABc)
    Debug.Print varComp1, varComp2, varComp3        ' -1 1 0
End Sub

[Python] Python 3 has no direct equivalent to StrComp, but the operator module provides similar functions (Table 6-7).

Table 6-7 String Comparison Functions in operator Module

Function Description
operator.lt(str1, str2) Returns True if str1 < str2.
operator.le(str1, str2) Returns True if str1 <= str2.
operator.eq(str1, str2) Returns True if str1 == str2.
operator.ne(str1, str2) Returns True if str1 != str2.
operator.gt(str1, str2) Returns True if str1 > str2.
operator.ge(str1, str2) Returns True if str1 >= str2.

Example:

code.python 
>>> import operator as op
>>> op.lt('a', 7;b')          # True(a < b)
>>> op.eq('a123', &#x27;a12b')    # False(a123 ≠ a12b)
>>> op.ge('forpython', &#x27;forvba')  # False(forpython < forvba)

Other string comparison functions (Table 6-8):

Table 6-8 Additional String Comparison Functions

Function Description
str.isalnum() True if all characters are alphanumeric.
str.isalpha() True if all characters are alphabetic.
str.isdigit() True if all characters are digits.
str.isnumeric() True if all characters are numeric.
str.islower() True if all letters are lowercase.
str.isupper() True if all letters are uppercase.
str.isspace() True if all characters are whitespace.
max(str) Largest character (by ASCII value).
min(str) Smallest character (by ASCII value).

Examples:

code.python 
>>> 'Abc123'.isalnum()  # True (letters and digits)
>>> 'Abc123'.isalpha()  # False (contains digits)
>>> '123123'.isdigit()  # True (all digits)
>>> '123.123'.isnumeric()  # False (contains '.')
>>> 'abc'.islower()     # True (all lowercase)
>>> max('Abc')          # 'c' (largest character)