从具有 Python 的列表中获取最大值
Get a maximum value from a list with Python
我有一个数据文件，我只需要第 3 列中包含的最大值。我写了下面的代码：
def testing():
file_reading = open("source_file.txt", "r", encoding="utf-8")
file_steps_yearly_sum = 0
file_steps_daily_list = []
while (True):
row = file_reading.readline()
if len(row) == 0:
break
else:
steps = row.split(';')[2]
file_steps_yearly_sum = int(file_steps_yearly_sum) + int(steps)
#file_steps_list.append(row.split(';')[2])
file_steps_daily_list.append(steps)
print(max(file_steps_daily_list))
print(file_steps_yearly_sum)
file_reading.close()
return file_steps_daily_list, file_steps_yearly_sum
计算的总和是正确的（用excel检查过），但是max方法给了我9928，这显然是错误的。只需查看输入文件，我就能看到目前的值远远超过 10 000。没看懂，应该是单行本
为了确定，用一个循环做了同样的事情：
def max_num_in_list(file_steps_daily_list):
max = file_steps_daily_list[ 0 ]
for steps in file_steps_daily_list:
if steps > max:
max = steps
return max
同样，9928。我从源文件的第 3 列中提取的列表是：
['3766', '12049', '14624', '12244', '12353', '12883', '11079', '10382', '11491', '14863', '8607', '15768', '9308', '10369', '11240', '12316', '14224', '10806', '9511', '7680', '12966', '11112', '14996', '15939 ', '11097', '5904', '15145', '9319', '15927', '11093', '8978', '9777', '10945', '9928', '12438', '10862', '12461', '11435', '15788', '10483', '5110', '15148', '12534', '12806', '14360', '10890', '11102', '6314', '10931 ', '12354', '6986', '14972', '13312', '10307', '9032', '10941', '8279', '10040', '14651', '8613', '7798', '13348', '10173', '15510', '15158', '13350', '10725', '8819', '17705', '12188', '10588', '9329', '9855', '8263 ', '8568', '7943', '20916', '15909', '23344', '14633', '31589', '17501', '15623', '27245', '14883', '13990', '11854', '12016', '4131', '5286', '6542', '6165', '9261', '11257', '11418', '5848', '6240', '4718', '10072 ', '7737', '6313', '13311', '14479', '6472', '6411', '7662', '8918', '13317', '17446', '5920', '7435', '9381', '12857', '7828', '8645', '12074', '12183', '8771', '4522', '5575', '8379', '8759', '8803', '7046', '12604', '10126', '11097', '8137 ', '6297', '10037', '5261', '5498', '10552', '4577', '8059', '5404', '4995', '8932', '6457', '10056', '9578', '11464', '11847', '5212', '13996', '11114', '8130', '10293', '9456', '12363', '8990', '11352', '5656 ', '15293', '5777', '8666', '8810', '8257', '6530', '10545', '8240', '10257', '8968', '10885', '14032', '14824', '14065', '9459', '11654', '13685', '20181', '11789', '15220', '17844', '17542', '9152', '11382', '9120 ', '10311', '14250', '19197', '22475', '12806', '13575', '7773', '4581', '14411', '10262', '25511', '17731', '10729', '16751', '13167', '14036', '12650', '11697', '12388', '14691', '18434', '5770', '9392', '9802', '10770 ', '10666', '10270', '12637', '16612', '10226', '9296', '6447', '10558', '8255', '11657', '10749', '10691', '10692', '10202', '10129', '6985', '8428', '13951', '10186', '7663', '10325', '8022', '6410', '13082', '8145 ', '8342', '6718', '7665', '4771' , '10337', '11529', '10757', '10578', '8330', '10803', '10465', '4351', '10575', '18682', '10668', '7541', ' 10318', '11217', '6072', '14779', '14593', '10970', '9538', '11130', '16437', '4732', '10523', '9428', '4023' , '8045', '9397', '12765', '8888', '11324', '10952', '8924', '10643', '11467', '15881', '11923', '13584', ' 13399'、'11940'、'10092'、'7739'、'9582'、'11673'、'8454'、'11401'、'10040'、'11706'、'10589'、'7475'、'9097' , '14294', '14672', '10227', '7452', '11680', '14223', '15035', '11698', '15239', '8878', '9530', '11068', ' 6766'、'10737'、'10805'、'13559'、'9126'、'10331'、'8525'、'4224'、'5898'、'7549'、'14848'、'11776'、'13216' , '8420', '6104', '6193', '7448', '8403', '7286', '11457', '11537', '4463', '6693', '3723', '12183', ' 10768'、'18342'、'13224'、'10874'、'7713'、'12385'、'14665'、'10184'、'10272'、'11718'、'12757'、'11296'、'18269' , '11295', '10987', '11690', '5036', '7402', '8013', '12001', '8734', '12941', '10298', '11536', '10947', ' 14931', '18185', '9139']
很明显，9928不是最大值。到底是怎么回事？为什么 max() 不给我最大值？
试试这个：
a = ['3766', '12049', '14624', '12244', '12353', '12883', '11079', '10382', '11491', '14863', '8607', '15768', '9308', '10369', '11240', '12316', '14224', '10806', '9511', '7680', '12966', '11112', '14996', '15939', '11097', '5904', '15145', '9319', '15927', '11093', '8978', '9777', '10945', '9928', '12438', '10862', '12461', '11435', '15788', '10483', '5110', '15148', '12534', '12806', '14360', '10890', '11102', '6314', '10931', '12354', '6986', '14972', '13312', '10307', '9032', '10941', '8279', '10040', '14651', '8613', '7798', '13348', '10173', '15510', '15158', '13350', '10725', '8819', '17705', '12188', '10588', '9329', '9855', '8263', '8568', '7943', '20916', '15909', '23344', '14633', '31589', '17501', '15623', '27245', '14883', '13990', '11854', '12016', '4131', '5286', '6542', '6165', '9261', '11257', '11418', '5848', '6240', '4718', '10072', '7737', '6313', '13311', '14479', '6472', '6411', '7662', '8918', '13317', '17446', '5920', '7435', '9381', '12857', '7828', '8645', '12074', '12183', '8771', '4522', '5575', '8379', '8759', '8803', '7046', '12604', '10126', '11097', '8137', '6297', '10037', '5261', '5498', '10552', '4577', '8059', '5404', '4995', '8932', '6457', '10056', '9578', '11464', '11847', '5212', '13996', '11114', '8130', '10293', '9456', '12363', '8990', '11352', '5656', '15293', '5777', '8666', '8810', '8257', '6530', '10545', '8240', '10257', '8968', '10885', '14032', '14824', '14065', '9459', '11654', '13685', '20181', '11789', '15220', '17844', '17542', '9152', '11382', '9120', '10311', '14250', '19197', '22475', '12806', '13575', '7773', '4581', '14411', '10262', '25511', '17731', '10729', '16751', '13167', '14036', '12650', '11697', '12388', '14691', '18434', '5770', '9392', '9802', '10770', '10666', '10270', '12637', '16612', '10226', '9296', '6447', '10558', '8255', '11657', '10749', '10691', '10692', '10202', '10129', '6985', '8428', '13951', '10186', '7663', '10325', '8022', '6410', '13082', '8145', '8342', '6718', '7665', '4771', '10337', '11529', '10757', '10578', '8330', '10803', '10465', '4351', '10575', '18682', '10668', '7541', '10318', '11217', '6072', '14779', '14593', '10970', '9538', '11130', '16437', '4732', '10523', '9428', '4023', '8045', '9397', '12765', '8888', '11324', '10952', '8924', '10643', '11467', '15881', '11923', '13584', '13399', '11940', '10092', '7739', '9582', '11673', '8454', '11401', '10040', '11706', '10589', '7475', '9097', '14294', '14672', '10227', '7452', '11680', '14223', '15035', '11698', '15239', '8878', '9530', '11068', '6766', '10737', '10805', '13559', '9126', '10331', '8525', '4224', '5898', '7549', '14848', '11776', '13216', '8420', '6104', '6193', '7448', '8403', '7286', '11457', '11537', '4463', '6693', '3723', '12183', '10768', '18342', '13224', '10874', '7713', '12385', '14665', '10184', '10272', '11718', '12757', '11296', '18269', '11295', '10987', '11690', '5036', '7402', '8013', '12001', '8734', '12941', '10298', '11536', '10947', '14931', '18185', '9139']
int_list = list(map(int,a))
print(max(int_list)) #31589
这看起来像一个字符串列表，max函数比较的是每个字符的char值，而不是数字的整数值。
首先将列表元素转换为 int，就像您对求和所做的那样。
print(max([int(i) for i in file_steps_daily_list]))
首先确保 steps 是一个 int 然后全面使用它
...
else:
steps = int(row.split(';')[2])
file_steps_yearly_sum = int(file_steps_yearly_sum) + steps
#file_steps_list.append(row.split(';')[2])
file_steps_daily_list.append(steps)
然后你可以打印
print(max(file_steps_daily_list))
我有一个数据文件，我只需要第 3 列中包含的最大值。我写了下面的代码：
def testing():
file_reading = open("source_file.txt", "r", encoding="utf-8")
file_steps_yearly_sum = 0
file_steps_daily_list = []
while (True):
row = file_reading.readline()
if len(row) == 0:
break
else:
steps = row.split(';')[2]
file_steps_yearly_sum = int(file_steps_yearly_sum) + int(steps)
#file_steps_list.append(row.split(';')[2])
file_steps_daily_list.append(steps)
print(max(file_steps_daily_list))
print(file_steps_yearly_sum)
file_reading.close()
return file_steps_daily_list, file_steps_yearly_sum
计算的总和是正确的（用excel检查过），但是max方法给了我9928，这显然是错误的。只需查看输入文件，我就能看到目前的值远远超过 10 000。没看懂，应该是单行本
为了确定，用一个循环做了同样的事情：
def max_num_in_list(file_steps_daily_list):
max = file_steps_daily_list[ 0 ]
for steps in file_steps_daily_list:
if steps > max:
max = steps
return max
同样，9928。我从源文件的第 3 列中提取的列表是：
['3766', '12049', '14624', '12244', '12353', '12883', '11079', '10382', '11491', '14863', '8607', '15768', '9308', '10369', '11240', '12316', '14224', '10806', '9511', '7680', '12966', '11112', '14996', '15939 ', '11097', '5904', '15145', '9319', '15927', '11093', '8978', '9777', '10945', '9928', '12438', '10862', '12461', '11435', '15788', '10483', '5110', '15148', '12534', '12806', '14360', '10890', '11102', '6314', '10931 ', '12354', '6986', '14972', '13312', '10307', '9032', '10941', '8279', '10040', '14651', '8613', '7798', '13348', '10173', '15510', '15158', '13350', '10725', '8819', '17705', '12188', '10588', '9329', '9855', '8263 ', '8568', '7943', '20916', '15909', '23344', '14633', '31589', '17501', '15623', '27245', '14883', '13990', '11854', '12016', '4131', '5286', '6542', '6165', '9261', '11257', '11418', '5848', '6240', '4718', '10072 ', '7737', '6313', '13311', '14479', '6472', '6411', '7662', '8918', '13317', '17446', '5920', '7435', '9381', '12857', '7828', '8645', '12074', '12183', '8771', '4522', '5575', '8379', '8759', '8803', '7046', '12604', '10126', '11097', '8137 ', '6297', '10037', '5261', '5498', '10552', '4577', '8059', '5404', '4995', '8932', '6457', '10056', '9578', '11464', '11847', '5212', '13996', '11114', '8130', '10293', '9456', '12363', '8990', '11352', '5656 ', '15293', '5777', '8666', '8810', '8257', '6530', '10545', '8240', '10257', '8968', '10885', '14032', '14824', '14065', '9459', '11654', '13685', '20181', '11789', '15220', '17844', '17542', '9152', '11382', '9120 ', '10311', '14250', '19197', '22475', '12806', '13575', '7773', '4581', '14411', '10262', '25511', '17731', '10729', '16751', '13167', '14036', '12650', '11697', '12388', '14691', '18434', '5770', '9392', '9802', '10770 ', '10666', '10270', '12637', '16612', '10226', '9296', '6447', '10558', '8255', '11657', '10749', '10691', '10692', '10202', '10129', '6985', '8428', '13951', '10186', '7663', '10325', '8022', '6410', '13082', '8145 ', '8342', '6718', '7665', '4771' , '10337', '11529', '10757', '10578', '8330', '10803', '10465', '4351', '10575', '18682', '10668', '7541', ' 10318', '11217', '6072', '14779', '14593', '10970', '9538', '11130', '16437', '4732', '10523', '9428', '4023' , '8045', '9397', '12765', '8888', '11324', '10952', '8924', '10643', '11467', '15881', '11923', '13584', ' 13399'、'11940'、'10092'、'7739'、'9582'、'11673'、'8454'、'11401'、'10040'、'11706'、'10589'、'7475'、'9097' , '14294', '14672', '10227', '7452', '11680', '14223', '15035', '11698', '15239', '8878', '9530', '11068', ' 6766'、'10737'、'10805'、'13559'、'9126'、'10331'、'8525'、'4224'、'5898'、'7549'、'14848'、'11776'、'13216' , '8420', '6104', '6193', '7448', '8403', '7286', '11457', '11537', '4463', '6693', '3723', '12183', ' 10768'、'18342'、'13224'、'10874'、'7713'、'12385'、'14665'、'10184'、'10272'、'11718'、'12757'、'11296'、'18269' , '11295', '10987', '11690', '5036', '7402', '8013', '12001', '8734', '12941', '10298', '11536', '10947', ' 14931', '18185', '9139']
很明显，9928不是最大值。到底是怎么回事？为什么 max() 不给我最大值？
试试这个：
a = ['3766', '12049', '14624', '12244', '12353', '12883', '11079', '10382', '11491', '14863', '8607', '15768', '9308', '10369', '11240', '12316', '14224', '10806', '9511', '7680', '12966', '11112', '14996', '15939', '11097', '5904', '15145', '9319', '15927', '11093', '8978', '9777', '10945', '9928', '12438', '10862', '12461', '11435', '15788', '10483', '5110', '15148', '12534', '12806', '14360', '10890', '11102', '6314', '10931', '12354', '6986', '14972', '13312', '10307', '9032', '10941', '8279', '10040', '14651', '8613', '7798', '13348', '10173', '15510', '15158', '13350', '10725', '8819', '17705', '12188', '10588', '9329', '9855', '8263', '8568', '7943', '20916', '15909', '23344', '14633', '31589', '17501', '15623', '27245', '14883', '13990', '11854', '12016', '4131', '5286', '6542', '6165', '9261', '11257', '11418', '5848', '6240', '4718', '10072', '7737', '6313', '13311', '14479', '6472', '6411', '7662', '8918', '13317', '17446', '5920', '7435', '9381', '12857', '7828', '8645', '12074', '12183', '8771', '4522', '5575', '8379', '8759', '8803', '7046', '12604', '10126', '11097', '8137', '6297', '10037', '5261', '5498', '10552', '4577', '8059', '5404', '4995', '8932', '6457', '10056', '9578', '11464', '11847', '5212', '13996', '11114', '8130', '10293', '9456', '12363', '8990', '11352', '5656', '15293', '5777', '8666', '8810', '8257', '6530', '10545', '8240', '10257', '8968', '10885', '14032', '14824', '14065', '9459', '11654', '13685', '20181', '11789', '15220', '17844', '17542', '9152', '11382', '9120', '10311', '14250', '19197', '22475', '12806', '13575', '7773', '4581', '14411', '10262', '25511', '17731', '10729', '16751', '13167', '14036', '12650', '11697', '12388', '14691', '18434', '5770', '9392', '9802', '10770', '10666', '10270', '12637', '16612', '10226', '9296', '6447', '10558', '8255', '11657', '10749', '10691', '10692', '10202', '10129', '6985', '8428', '13951', '10186', '7663', '10325', '8022', '6410', '13082', '8145', '8342', '6718', '7665', '4771', '10337', '11529', '10757', '10578', '8330', '10803', '10465', '4351', '10575', '18682', '10668', '7541', '10318', '11217', '6072', '14779', '14593', '10970', '9538', '11130', '16437', '4732', '10523', '9428', '4023', '8045', '9397', '12765', '8888', '11324', '10952', '8924', '10643', '11467', '15881', '11923', '13584', '13399', '11940', '10092', '7739', '9582', '11673', '8454', '11401', '10040', '11706', '10589', '7475', '9097', '14294', '14672', '10227', '7452', '11680', '14223', '15035', '11698', '15239', '8878', '9530', '11068', '6766', '10737', '10805', '13559', '9126', '10331', '8525', '4224', '5898', '7549', '14848', '11776', '13216', '8420', '6104', '6193', '7448', '8403', '7286', '11457', '11537', '4463', '6693', '3723', '12183', '10768', '18342', '13224', '10874', '7713', '12385', '14665', '10184', '10272', '11718', '12757', '11296', '18269', '11295', '10987', '11690', '5036', '7402', '8013', '12001', '8734', '12941', '10298', '11536', '10947', '14931', '18185', '9139']
int_list = list(map(int,a))
print(max(int_list)) #31589
这看起来像一个字符串列表，max函数比较的是每个字符的char值，而不是数字的整数值。
首先将列表元素转换为 int，就像您对求和所做的那样。
print(max([int(i) for i in file_steps_daily_list]))
首先确保 steps 是一个 int 然后全面使用它
...
else:
steps = int(row.split(';')[2])
file_steps_yearly_sum = int(file_steps_yearly_sum) + steps
#file_steps_list.append(row.split(';')[2])
file_steps_daily_list.append(steps)
然后你可以打印
print(max(file_steps_daily_list))