Python之Pandas：pandas.DataFrame.to_csv函数的简介、具体案例、使用方法详细攻略

Bertha 。 2022-11-20 08:22 248阅读 0赞

Python之Pandas：pandas.DataFrame.to\_csv函数的简介、具体案例、使用方法详细攻略

**目录**

pandas.DataFrame.to\_csv函数的简介

pandas.to\_csv()函数的具体案例

--------------------

## pandas.DataFrame.to\_csv函数的简介 ##

`DataFrame.``to_csv`(*path\_or\_buf=None*, *sep=','*, *na\_rep=''*, *float\_format=None*, *columns=None*, *header=True*, *index=True*, *index\_label=None*, *mode='w'*, *encoding=None*, *compression='infer'*, *quoting=None*, *quotechar='"'*, *line\_terminator=None*, *chunksize=None*, *date\_format=None*, *doublequote=True*, *escapechar=None*, *decimal='.'*, *errors='strict'*)

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 <td style="width:482px;"> def to_csv Found at: pandas.core.generic def to_csv( &nbsp; &nbsp; self,&nbsp; &nbsp; &nbsp; path_or_buf:Optional[FilePathOrBuffer]=None,&nbsp; &nbsp; &nbsp; sep:str=",",&nbsp; &nbsp; &nbsp; na_rep:str="",&nbsp; &nbsp; &nbsp; float_format:Optional[str]=None,&nbsp; &nbsp; &nbsp; columns:Optional[Sequence[Label]]=None,&nbsp; &nbsp; &nbsp; header:Union[bool_tList[str]]=True,&nbsp; &nbsp; &nbsp; index:bool_t=True,&nbsp; &nbsp; &nbsp; index_label:Optional[Union[bool_tstrSequence[Label]]] &nbsp; &nbsp; &nbsp;=None,&nbsp; &nbsp; &nbsp; mode:str="w",&nbsp; &nbsp; &nbsp; encoding:Optional[str]=None,&nbsp; &nbsp; &nbsp; compression:Optional[Union[strMapping[strstr]]]="infer",&nbsp; &nbsp; &nbsp; quoting:Optional[int]=None,&nbsp; &nbsp; &nbsp; quotechar:str='"',&nbsp; &nbsp; &nbsp; line_terminator:Optional[str]=None,&nbsp; &nbsp; &nbsp; chunksize:Optional[int]=None,&nbsp; &nbsp; &nbsp; date_format:Optional[str]=None,&nbsp; &nbsp; &nbsp; doublequote:bool_t=True,&nbsp; &nbsp; &nbsp; escapechar:Optional[str]=None,&nbsp; &nbsp; &nbsp; decimal:Optional[str]=".",&nbsp; &nbsp; &nbsp; errors:str="strict")-&gt; Optional[str]: &nbsp; &nbsp; r""" &nbsp; &nbsp; Write object to a comma-separated values (csv) file. &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; .. versionchanged:: 0.24.0 &nbsp; &nbsp; The order of arguments for Series was changed. </td> 
 <td style="width:416px;">将对象写入逗号分隔值(csv)文件。</td> 
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 <td style="width:482px;"> &nbsp; &nbsp; Parameters &nbsp; &nbsp; ---------- &nbsp; &nbsp; path_or_buf : str or file handle, default None. File path or object, if None is provided the result is returned&nbsp;as a string. &nbsp;If a file object is passed it should be opened with `newline=''`, disabling universal newlines. &nbsp; &nbsp; .. versionchanged:: 0.24.0 &nbsp; &nbsp; Was previously named "path" for Series. &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; sep : str, default ','. String of length 1. Field delimiter for the output file. &nbsp; &nbsp; na_rep : str, default ''. Missing data representation. &nbsp; &nbsp; float_format : str, default None. Format string for floating point numbers. &nbsp; &nbsp; columns : sequence, optional. Columns to write. &nbsp; &nbsp; header : bool or list of str, default True.Write out the column names. If a list of strings is given it is assumed to be aliases for the column names. &nbsp; &nbsp; .. versionchanged:: 0.24.0 &nbsp; &nbsp; Previously defaulted to False for Series. &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; index : bool, default True. Write row names (index). &nbsp; &nbsp; index_label : str or sequence, or False, default None. Column label for index column(s) if desired. If None is given,&nbsp; and `header` and `index` are True, then the index names are used.&nbsp; A sequence should be given if the object uses MultiIndex. If&nbsp;&nbsp;False do not print fields for index names. Use&nbsp;&nbsp;&nbsp;index_label=False for easier importing in R. &nbsp; &nbsp; mode : str.Python write mode, default 'w'. &nbsp; &nbsp; encoding : str, optional.A string representing the encoding to use in the output file, defaults to 'utf-8'. &nbsp; &nbsp; compression : str or dict, default 'infer'. If str, represents compression mode. If dict, value at 'method'&nbsp; is&nbsp;&nbsp;the compression mode. Compression mode may be any of&nbsp;the following &nbsp; &nbsp; possible values: {'infer', 'gzip', 'bz2', 'zip', 'xz', None}. If compression mode is 'infer' and `path_or_buf` is path-like,&nbsp;then detect compression mode from the following extensions: '. gz', '.bz2', '.zip' or '.xz'. (otherwise no compression). If dict given&nbsp;&nbsp;and mode is one of {'zip', 'gzip', 'bz2'}, or inferred as one of the above, other entries passed as additional compression options. &nbsp; &nbsp;.. versionchanged:: 1.0.0 &nbsp; &nbsp; May now be a dict with key 'method' as compression mode and other entries as additional compression options if compression mode is 'zip'. &nbsp; &nbsp; .. versionchanged:: 1.1.0 &nbsp; &nbsp; Passing compression options as keys in dict is&nbsp;&nbsp;supported for compression modes 'gzip' and 'bz2'&nbsp;&nbsp;as well as 'zip'. </td> 
 <td style="width:416px;"> 参数 ---------- path_or_buf :&nbsp;&nbsp;str或file handle，默认无。文件路径或对象，如果没有提供，结果将作为字符串返回。如果一个文件对象被传递，它应该被打开' newline= " '，禁用通用换行。 . .versionchanged: 0.24.0 之前被命名为“path”系列。 sep : str，默认为'，'。长度为1的字符串。输出文件的字段分隔符。 na_rep :&nbsp; str，默认值"。缺失的数据表示。 float_format :&nbsp;&nbsp;str，默认没有。浮点数的格式字符串。 columns :&nbsp;&nbsp;序列，可选。列写。 header :&nbsp;&nbsp;bool或str列表，默认为True。写出列名。如果给定了字符串列表，则假定它是列名的别名。 . .versionchanged: 0.24.0 以前对于级数默认为False。 index :&nbsp;&nbsp;bool，默认为True。写行名称(索引)。 
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 <li>cats_df_temp.to_csv(cats_csv_file,index=None)&nbsp;&nbsp; #输出不加默认的索引列</li> 
 </ul>iindex_label :&nbsp; str或序列，或False，默认无。如果需要，用于索引列的列标签。如果没有给出，并且' header '和' index '为真，则使用索引名。如果对象使用多索引，则应该给出一个序列。如果为False，不要打印索引名称的字段。使用index_label=False在R中更容易导入。 mode :&nbsp;str.Python编写模式，默认为“w”。 encoding :&nbsp;str，可选。表示要在输出文件中使用的编码的字符串，默认为“utf-8”。 compression :&nbsp;str或dict，默认为'infer'。如果为str，表示压缩模式。如果是dict, value at 'method'是压缩模式。压缩模式可以是下列任何一种 possible values:&nbsp; &nbsp;{'infer', 'gzip', 'bz2', 'zip', 'xz', None}.。如果压缩模式是'infer'，而' path_or_buf '是类似路径的，那么从以下扩展中检测压缩模式:'。 '. gz', '.bz2', '.zip' or '.xz'. 。(否则不压缩)。如果dict given和mode是{'zip'、'gzip'、'bz2'}或推断为上述选项之一，则其他项作为附加压缩选项传递。 . .versionchanged: 1.0.0 如果压缩模式是“zip”，则可以使用关键的“方法”作为压缩模式，其他条目作为附加的压缩选项。 . .versionchanged: 1.1.0 压缩模式“gzip”和“bz2”以及“zip”支持将压缩选项作为键在dict中传递。 </td> 
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 <td style="width:482px;"> &nbsp; &nbsp;quoting : optional constant from csv module. Defaults to csv.QUOTE_MINIMAL. If you have set a&nbsp; `float_format` then floats are converted to strings and thus csv. QUOTE_NONNUMERIC will treat them as non-numeric. &nbsp; &nbsp; quotechar : str, default '\"'. String of length 1. Character used to quote fields. &nbsp; &nbsp; line_terminator : str, optional. The newline character or character sequence to use in the&nbsp; output file. Defaults to `os.linesep`, which depends on the OS in which this method is called ('\n' for linux, '\r\n' for Windows, i.e.). &nbsp; &nbsp; .. versionchanged:: 0.24.0 &nbsp; &nbsp; chunksize : int or None. Rows to write at a time. &nbsp; &nbsp; date_format : str, default None.Format string for datetime objects. &nbsp; &nbsp; doublequote : bool, default True. Control quoting of `quotechar` inside a field. &nbsp; &nbsp; escapechar : str, default None. String of length 1. Character used to escape `sep` and&nbsp; `quotechar` when appropriate. &nbsp; &nbsp; decimal : str, default '.'. Character recognized as decimal separator. E.g. use ',' for European data. &nbsp; &nbsp; errors : str, default 'strict'.Specifies how encoding and decoding errors are to be&nbsp;handled. See the errors argument for :func:`open` for a full list of options. &nbsp; &nbsp; .. versionadded:: 1.1.0 </td> 
 <td style="width:416px;">quoting :&nbsp;&nbsp;csv模块中的可选常量。默认为csv.QUOTE_MINIMAL。如果你设置了一个' float_format '，那么float就会被转换为字符串，从而转换为csv。QUOTE_NONNUMERIC将把它们视为非数值。 quoting : str，默认为'\"'。长度为1的字符串。用于引用字段的字符。 line_terminator : str，可选。输出文件中要使用的换行字符或字符序列。默认的操作系统。linesep '，它取决于调用该方法的操作系统(例如，linux是'\n'， Windows是'\r\n')。 . .versionchanged: 0.24.0 chunksize :&nbsp;int或None。每次要写入的行。 date_format :&nbsp;&nbsp;str，默认无。日期时间对象的格式字符串。 doublequote :bool，默认为True。控制字段内引用“quotechar”。 escapechar :&nbsp;str，默认无。长度为1的字符串。在适当的时候，字符用于转义' sep '和' quotechar '。 decimal :&nbsp;&nbsp;str，默认为'.'。可识别为十进制分隔符的字符。例如，使用“，”表示欧洲数据。 errors :&nbsp;&nbsp;str，默认为“strict”。指定如何处理编码和解码错误。查看:func: ' open '的错误参数以获得选项的完整列表。 . .versionadded: 1.1.0</td> 
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 <td style="width:482px;">&nbsp; &nbsp; Returns &nbsp; &nbsp; ------- &nbsp; &nbsp; None or str.&nbsp;&nbsp;If path_or_buf is None, returns the resulting csv format as a string. Otherwise returns None. &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; See Also &nbsp; &nbsp; -------- &nbsp; &nbsp; read_csv : Load a CSV file into a DataFrame. &nbsp; &nbsp; to_excel : Write DataFrame to an Excel file.</td> 
 <td style="width:416px;">返回 ------- 如果path_or_buf为None，则返回结果csv格式为字符串。否则返回None。 另请参阅 &nbsp;-------- read_csv:将CSV文件加载到一个DataFrame中。 to_excel:将DataFrame写入Excel文件。</td> 
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 <td style="width:482px;"> &nbsp; &nbsp; Examples &nbsp; &nbsp; -------- &nbsp; &nbsp; &gt;&gt;&gt; df = pd.DataFrame({'name': ['Raphael', 'Donatello'], &nbsp; &nbsp; ... &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;'mask': ['red', 'purple'], &nbsp; &nbsp; ... &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;'weapon': ['sai', 'bo staff']}) &nbsp; &nbsp; &gt;&gt;&gt; df.to_csv(index=False) &nbsp; &nbsp; 'name,mask,weapon\nRaphael,red,sai\nDonatello,purple,bo&nbsp; &nbsp; &nbsp; &nbsp;staff\n' &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; Create 'out.zip' containing 'out.csv' &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &gt;&gt;&gt; compression_opts = dict(method='zip', &nbsp; &nbsp; ... &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; archive_name='out.csv') &nbsp;# doctest: +SKIP &nbsp; &nbsp; &gt;&gt;&gt; df.to_csv('out.zip', index=False, &nbsp; &nbsp; ... &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; compression=compression_opts) &nbsp;# doctest: +SKIP &nbsp; &nbsp; """ &nbsp; &nbsp; df = self if isinstance(self, ABCDataFrame) else self.to_frame() &nbsp; &nbsp; from pandas.io.formats.csvs import CSVFormatter &nbsp; &nbsp; formatter = CSVFormatter( &nbsp; &nbsp; &nbsp; &nbsp; df,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; path_or_buf,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; line_terminator=line_terminator,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; sep=sep,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; encoding=encoding,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; errors=errors,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; compression=compression,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; quoting=quoting,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; na_rep=na_rep,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; float_format=float_format,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; cols=columns,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; header=header,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; index=index,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; index_label=index_label,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; mode=mode,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; chunksize=chunksize,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; quotechar=quotechar,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; date_format=date_format,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; doublequote=doublequote,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; escapechar=escapechar,&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; decimal=decimal) &nbsp; &nbsp; formatter.save() &nbsp; &nbsp; if path_or_buf is None: &nbsp; &nbsp; &nbsp; &nbsp; return formatter.path_or_buf.getvalue() &nbsp; &nbsp; return None # ---------------------------------------------------------------------- # Lookup Caching </td> 
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## pandas.to\_csv()函数的具体案例 ##

df = pd.DataFrame({'name': ['Raphael', 'Donatello'],
                       'mask': ['red', 'purple'],
                       'weapon': ['sai', 'bo staff']})
    df.to_csv(index=False)
    'name,mask,weapon\nRaphael,red,sai\nDonatello,purple,bo staff\n'
    
    
    compression_opts = dict(method='zip',
                            archive_name='out.csv')  
    df.to_csv('out.zip', index=False,
              compression=compression_opts)