python查找文件中某个字符串出现的次数

'''查找文件中某个字符串总共出现的次数'''
def findStr(str):
    with open("filePath",'r') as f:
        counts = 0
        for line in f.readlines():
            time = line.count(str)
            counts += time
        print("%s出现的次数：%d"%(str,counts))

findStr("str")