Python 如何检索 Pandas 数据框中的列数？
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How do I retrieve the number of columns in a Pandas data frame?
提问by user1802143
How do you programmatically retrieve the number of columns in a pandas dataframe? I was hoping for something like:
如何以编程方式检索 Pandas 数据框中的列数？我希望是这样的：
df.num_columns
采纳答案by John
Like so:
像这样：
import pandas as pd
df = pd.DataFrame({"pear": [1,2,3], "apple": [2,3,4], "orange": [3,4,5]})
len(df.columns)
3
回答by mkln
Alternative:
选择：
df.shape[1]
(df.shape[0]is the number of rows)
（df.shape[0]是行数）
回答by multigoodverse
If the variable holding the dataframe is called df, then:
如果保存数据帧的变量称为 df，则：
len(df.columns)
gives the number of columns.
给出列数。
And for those who want the number of rows:
对于那些想要行数的人：
len(df.index)
For a tuple containing the number of both rows and columns:
对于包含行数和列数的元组：
df.shape
回答by Tanmay Ghanekar
This worked for me len(list(df)).
这对我有用 len(list(df))。
回答by AshishSingh007
df.info() function will give you result something like as below. If you are using read_csv method of Pandas without sep parameter or sep with ",".
df.info() 函数会给你如下结果。如果您使用的是不带 sep 参数或带“,”的 sep 的 Pandas 的 read_csv 方法。
raw_data = pd.read_csv("a1:\aa2/aaa3/data.csv")
raw_data.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5144 entries, 0 to 5143
Columns: 145 entries, R_fighter to R_age
回答by AshishSingh007
There are multiple option to get column number and column information such as:
let's check them.
有多种选项可以获取列号和列信息，例如：
让我们检查一下。
local_df = pd.DataFrame(np.random.randint(1,12,size=(2,6)),columns =['a','b','c','d','e','f']) 1. local_df.shape[1] --> Shape attribute return tuple as (row & columns) (0,1).
local_df = pd.DataFrame(np.random.randint(1,12,size=(2,6)),columns =['a','b','c','d','e','f ']) 1. local_df.shape[1] --> Shape 属性返回元组为（行和列）（0,1）。
local_df.info() --> info Method will return detailed information about data frame and it's columns such column count, data type of columns, Not null value count, memory usage by Data Frame
len(local_df.columns) --> columns attribute will return index object of data frame columns & len function will return total available columns.
local_df.head(0) --> head method with parameter 0 will return 1st row of df which actually nothing but header.
local_df.info() --> info 方法将返回有关数据框及其列的详细信息，例如列数、列的数据类型、非空值计数、数据框的内存使用情况
len(local_df.columns) --> columns 属性将返回数据框列的索引对象，len 函数将返回可用列的总数。
local_df.head(0) --> 参数为 0 的 head 方法将返回 df 的第一行，它实际上只是标题。
Assuming number of columns are not more than 10. For loop fun: li_count =0 for x in local_df: li_count =li_count + 1 print(li_count)
假设列数不超过 10。for 循环乐趣：li_count =0 for x in local_df: li_count =li_count + 1 print(li_count)
