import polars as pl import time # 读取 CSV 文件 start = time.time() df_pl = pl.read_csv('test_data.csv') load_time_pl = time.time() - start # 过滤操作 start = time.time() filtered_pl = df_pl.filter(pl.col('value1') >
array_split(df, num_chunks)): filename = f"output_{i}.csv" chunk.to_csv(filename, index=False) Python Copy这段代码将DataFrame对象分割成了2个文件:output_0.csv和output_1.csv。每个文件最多包含3行数据,我们可以打开这两个文件看一下输出内容:...
#方法一、用agg汇总后再merge到原表 df_wrong = df_cls_price.reset_index() #把datetime64的索引变成列,列名为Date df_wrong['month'] = df_wrong['Date'].apply(lambda x: str(x)[:7]) # 生成month辅助列 #得到月均价 df_wrong_avgprice = (df_wrong .groupby('month') .mean() ) #把月均...
False, float_precision=None, storage_options: 'StorageOptions' = None)Read a comma-separated values (csv) file into DataFrame.Also supports optionally iterating or breaking of the fileinto chunks.Additional help can be found in the online docs for`IO Tools <https://pandas.pydata.org/pandas-...
import pandas as pd data = {'Name': ['Alice', 'Bob', 'Charlie', 'David'], 'Age': [24, 17, 35, 19]} df = pd.DataFrame(data) Step2: Define the Boolean Criterion: criterion = df['Age'] >= 18 Step 3: Split the DataFrame: df_adults = df[criterion] df_minors = df[~criter...
Split the data into chunks You’ll take a look at each of these techniques in turn. Compress and Decompress Files You can create an archive file like you would a regular one, with the addition of a suffix that corresponds to the desired compression type: '.gz' '.bz2' '.zip' '.xz'...
How to Split a Pandas DataFrame into Chunks Pandas: Count the unique combinations of two Columns Pandas: Set number of max Rows and Cols shown in DataFrameI wrote a book in which I share everything I know about how to become a better, more efficient programmer. You can use the search fi...
Load less data:While reading data usingpd.read_csv(), choose only the columns you need with the “usecols” parameter to avoid loading unnecessary data. Plus, specifying the “chunksize” parameter splits the data into different chunks and processes them sequentially. ...
Pull requests97 Actions Projects Security Insights Additional navigation options BUG: FutureWarning when splitting a dataframe usingnp.split#57351 New issue Open Description amanlai amanlai added Bug Needs TriageIssue that has not been reviewed by a pandas team member ...
df = pd.read_json('data.json', orient='split') print(df) Output: name age city 0 John 44 New York 1 Alice 25 San Francisco records The'records'orientation interprets each element in the JSON data as a separate record, represented by a dictionary. ...