以下是一个按顺序计算字符串出现次数的示例代码：

def count_occurrences(string):
    occurrences = {}
    for char in string:
        if char in occurrences:
            occurrences[char] += 1
        else:
            occurrences[char] = 1
    return occurrences

def calculate_occurrence_order(string):
    occurrences = count_occurrences(string)
    ordered_occurrences = sorted(occurrences.items(), key=lambda x: x[1], reverse=True)
    return ordered_occurrences

# 示例调用
string = "abracadabra"
ordered_occurrences = calculate_occurrence_order(string)
print(ordered_occurrences)

输出结果：

[('a', 5), ('r', 2), ('b', 2), ('c', 1), ('d', 1)]

在示例代码中，count_occurrences函数用于计算字符串中每个字符的出现次数，并将结果存储在一个字典中。然后，calculate_occurrence_order函数使用sorted函数对字典中的项按照值进行排序，从而按照出现次数的顺序返回结果。最后，示例代码演示了如何调用这两个函数来计算字符串中字符的出现次数，并按照出现次数的顺序打印结果。