我正在尝试使用熊猫读取csv
文件
df1 = pd.read_csv('panda_error.csv', header=None, sep=',')
但是我收到此错误:
ParserError: Error tokenizing data. C error: Expected 7 fields in line 4, saw 10
为了再现性,这是csv文件panda_error.csv
superkingdom:Bacteria , phylum:Actinobacteria , class:Actinobacteria , order:Corynebacteriales , family:Corynebacteriaceae , genus:Corynebacterium , species:Corynebacterium efficiens 1
superkingdom:Bacteria , phylum:Proteobacteria , class:Alphaproteobacteria , order:Rhizobiales , family:Aurantimonadaceae , genus:Aurantimonas , species:Aurantimonas manganoxydans 1
superkingdom:Bacteria , phylum:Proteobacteria , subphylum:delta/epsilon subdivisions , class:Deltaproteobacteria , no rank:unclassified Deltaproteobacteria , genus:Candidatus Entotheonella 1
superkingdom:Bacteria , phylum:Proteobacteria , class:Gammaproteobacteria , order:Pseudomonadales , family:Pseudomonadaceae , genus:Pseudomonas , species group:Pseudomonas syringae group , species subgroup:Pseudomonas syringae group genomosp. 2 , species:Pseudomonas amygdali , no rank:Pseudomonas amygdali pv. tabaci 1
superkingdom:Bacteria , phylum:Actinobacteria , class:Actinobacteria , order:Corynebacteriales , family:Nocardiaceae , genus:Rhodococcus , species:Rhodococcus wratislaviensis 1
superkingdom:Bacteria , phylum:Firmicutes , class:Clostridia , order:Clostridiales , family:Peptostreptococcaceae , genus:Peptoclostridium , species:Peptoclostridium difficile1
我不太确定为什么会这样以及如何解决。其他答案只是建议1.忽略我不想使用的error_bad_lines=False
造成的麻烦,或2.特定情况下的麻烦。
如果有帮助,这里是完整的错误消息:
---------------------------------------------------------------------------
ParserError Traceback (most recent call last)
<ipython-input-34-72c0ecaf0513> in <module>
----> 1 df1 = pd.read_csv('panda_error.csv', header=None, sep=',')
/opt/anaconda3/lib/python3.7/site-packages/pandas/io/parsers.py in parser_f(filepath_or_buffer, sep, delimiter, header, names, index_col, usecols, squeeze, prefix, mangle_dupe_cols, dtype, engine, converters, true_values, false_values, skipinitialspace, skiprows, skipfooter, nrows, na_values, keep_default_na, na_filter, verbose, skip_blank_lines, parse_dates, infer_datetime_format, keep_date_col, date_parser, dayfirst, cache_dates, iterator, chunksize, compression, thousands, decimal, lineterminator, quotechar, quoting, doublequote, escapechar, comment, encoding, dialect, error_bad_lines, warn_bad_lines, delim_whitespace, low_memory, memory_map, float_precision)
683 )
684
--> 685 return _read(filepath_or_buffer, kwds)
686
687 parser_f.__name__ = name
/opt/anaconda3/lib/python3.7/site-packages/pandas/io/parsers.py in _read(filepath_or_buffer, kwds)
461
462 try:
--> 463 data = parser.read(nrows)
464 finally:
465 parser.close()
/opt/anaconda3/lib/python3.7/site-packages/pandas/io/parsers.py in read(self, nrows)
1152 def read(self, nrows=None):
1153 nrows = _validate_integer("nrows", nrows)
-> 1154 ret = self._engine.read(nrows)
1155
1156 # May alter columns / col_dict
/opt/anaconda3/lib/python3.7/site-packages/pandas/io/parsers.py in read(self, nrows)
2057 def read(self, nrows=None):
2058 try:
-> 2059 data = self._reader.read(nrows)
2060 except StopIteration:
2061 if self._first_chunk:
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader.read()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._read_low_memory()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._read_rows()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._tokenize_rows()
pandas/_libs/parsers.pyx in pandas._libs.parsers.raise_parser_error()
ParserError: Error tokenizing data. C error: Expected 7 fields in line 4, saw 10
This solution为我工作
### Loop the data lines
with open("panda_error.csv", 'r') as temp_f:
# get No of columns in each line
col_count = [ len(l.split(",")) for l in temp_f.readlines() ]
### Generate column names (names will be 0, 1, 2, ..., maximum columns - 1)
column_names = [i for i in range(0, max(col_count))]
### Read csv
df = pd.read_csv("panda_error.csv", header=None, delimiter=",", names=column_names)
Pandas是用于处理表格数据的工具。这意味着每一行应包含相同数量的字段。如果输入CSV,则还有一个要求,即字段每行中的<。但是您的输入文件实际上不能同时满足这两个要求。
[前2行(可能还有其他大多数行)具有7个字段:
超级王国
,门,类,顺序,家庭,属和物种。第三行包含:超级王国
,门,子门,类别,无等级和属。因此:read_csv失败,仅是因为字段数不超过上一行中的字段数(总共有[[6
个字段)。但是真正的问题是在第4行中,其中有10个字段。所以“普通” read_csv
在这里绝不是任何好的选择。即使您将列数设置为足以读取所有行,属性将以难以阅读的方式“分散”在列之间。任何基于列名分析此类数据的尝试都会失败,因为每一列在不同的行中都有不同的信息。
另一个问题是,用逗号分隔的数据将包含例如超级王国:细菌
,即:应该是列(属性)的文本名称
单个列(sep
df = pd.read_csv('input.csv', sep='|', names=['col1'])
下一步,导致可以通过以下方式分析的DataFrame一个程序是
import re
):df2 = df.col1.str.extractall(
r'(?P<name>[A-Z ]+[A-Z]):(?P<value>[A-Z /]+[A-Z])', flags=re.I)\
.reset_index(level=1, drop=True)
如果您不熟练使用正则表达式,请阅读一些有关它们的内容。结果是一个具有两列的DataFrame:
0
开始。对于您的样本数据,结果如下: name value
0 superkingdom Bacteria
0 phylum Actinobacteria
0 class Actinobacteria
0 order Corynebacteriales
0 family Corynebacteriaceae
0 genus Corynebacterium
0 species Corynebacterium efficiens
1 superkingdom Bacteria
1 phylum Proteobacteria
1 class Alphaproteobacteria
1 order Rhizobiales
1 family Aurantimonadaceae
1 genus Aurantimonas
1 species Aurantimonas manganoxydans
2 superkingdom Bacteria
2 phylum Proteobacteria
2 subphylum delta/epsilon subdivisions
2 class Deltaproteobacteria
2 no rank unclassified Deltaproteobacteria
2 genus Candidatus Entotheonella
3 superkingdom Bacteria
3 phylum Proteobacteria
3 class Gammaproteobacteria
3 order Pseudomonadales
3 family Pseudomonadaceae
3 genus Pseudomonas
3 species group Pseudomonas syringae group
3 species subgroup Pseudomonas syringae group genomosp
3 species Pseudomonas amygdali
3 no rank Pseudomonas amygdali pv
4 superkingdom Bacteria
4 phylum Actinobacteria
4 class Actinobacteria
4 order Corynebacteriales
4 family Nocardiaceae
4 genus Rhodococcus
4 species Rhodococcus wratislaviensis
5 superkingdom Bacteria
5 phylum Firmicutes
5 class Clostridia
5 order Clostridiales
5 family Peptostreptococcaceae
5 genus Peptoclostridium
5 species Peptoclostridium difficile
如果您想将这些数据作为表格并转换为每个
name到相应的列,运行:
df3 = df2.set_index('name', append=True).unstack(fill_value='')
df3.columns = df3.columns.droplevel()