如何计算一项在一列中存在的次数？

def count_occurrences(data, target):
    count = 0
    for item in data:
        if item == target:
            count += 1
    return count

# 示例用法
data = [1, 2, 3, 4, 2, 1, 2, 3, 2]
target = 2
occurrences = count_occurrences(data, target)
print("目标项 {} 在列中出现的次数为: {}".format(target, occurrences))